Pyrimidine hydroxy amide compounds as histone deacetylase inhibitors

ABSTRACT

Provided herein are compounds, pharmaceutical compositions comprising such compounds, and methods of using such compounds to treat or prevent diseases or disorders associated with HDAC activity, particularly diseases or disorders that involve activity of HDAC1, HDAC2, and/or HDAC6. Also provided herein are methods for inhibiting migration of a neuroblastoma cell, inducing maturation of a neuroblastoma cell, and altering cell cycle progression of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No. 14/510,711, filed Oct. 9, 2014, which claims priority to U.S. Provisional Application Ser. No. 61/889,295, filed Oct. 10, 2013; 61/944,754, filed Feb. 26, 2014; and 61/979,694, filed Apr. 15, 2014; each of which is incorporated herein by reference in its entirety.

BACKGROUND

A biological target of recent interest is histone deacetylase (HDAC) (see, for example, a discussion of the use of inhibitors of histone deacetylases for the treatment of cancer: Marks et al. Nature Reviews Cancer 2001, 7, 194; Johnstone et al. Nature Reviews Drug Discovery 2002, 287). Post-translational modification of proteins through acetylation and deacetylation of lysine residues plays a critical role in regulating their cellular functions. HDACs are zinc hydrolases that modulate gene expression through deacetylation of the N-acetyl-lysine residues of histone proteins and other transcriptional regulators (Hassig et al. Curr. Opin. Chem. Biol. 1997, 1, 300-308). HDACs participate in cellular pathways that control cell shape and differentiation, and an HDAC inhibitor has been shown to be effective in treating an otherwise recalcitrant cancer (Warrell et al. J. Natl. Cancer Inst. 1998, 90, 1621-1625).

At this time, eleven human HDACs, which use Zn as a cofactor, have been identified (Taunton et al. Science 1996, 272, 408-411; Yang et al. J. Biol. Chem. 1997, 272, 28001-28007. Grozinger et al. Proc. Natl. Acad. Sci. U.S.A. 1999, 96, 4868-4873; Kao et al. Genes Dev. 2000, 14, 55-66. Hu et al. J. Biol. Chem. 2000, 275, 15254-15264; Zhou et al. Proc. Natl. Acad. Sci U.S.A. 2001, 98, 10572-10577; Venter et al. Science 2001, 291, 1304-1351) and these members fall into three classes (class I, II, and IV) based on sequence homology to their yeast orthologues (O. Witt et al. Cancer Letters, 2009, 277, 8-21). Class I HDACs include HDAC1, HDAC2, HDAC3, and HDAC8, and are referred to as “classical” HDACs, which implies a catalytic pocket with a Zn²⁺ ion at its base.

There remains a need for preparing structurally diverse HDAC inhibitors, particularly ones that are potent and/or selective inhibitors of particular classes of HDACs and individual HDACs.

SUMMARY OF THE INVENTION

Provided herein are compounds, pharmaceutical compositions comprising such compounds, and methods of using such compounds to treat or prevent diseases or disorders associated with HDAC activity, particularly diseases or disorders that involve any type of HDAC1, HDAC2, and/or HDAC6 expression. Diseases that involve HDAC1, HDAC2 and/or HDAC6 expression include, but are not limited to, various types of cancer, neurodegenerative diseases, and hemoglobinopathies, such as sickle-cell anemia and beta-thalassemia.

Thus, in one aspect, provided herein is a compound of Formula I:

-   -   or a pharmaceutically acceptable salt thereof.

In a particular embodiment of the invention, provided herein is a compound of Formula II:

-   -   or a pharmaceutically acceptable salt thereof.

In a particular embodiment of the invention, provided herein is a compound of Formula III:

In another aspect, provided herein is a pharmaceutical composition comprising a compound of Formula I, Formula II, Formula III, or any of the compounds presented in Table 1, or pharmaceutically acceptable salts thereof, together with a pharmaceutically acceptable carrier.

In another aspect, provided herein is a method of inhibiting the activity of HDAC1, HDAC2, and/or HDAC6 in a subject comprising administering to the subject a compound of Formula I, Formula II, Formula III, or any of the compounds presented in Table 1, or a pharmaceutically acceptable salt thereof.

In another aspect, provided herein is a method of selectively inhibiting the activity of each of HDAC1, HDAC2, and/or HDAC6 over other HDACs in a subject comprising administering to the subject a compound of Formula I, Formula II, Formula III, or any of the compounds presented in Table 1, or a pharmaceutically acceptable salt thereof. In some embodiments, the compound has a selectivity for each of HDAC1, HDAC2, and/or HDAC6 that is 5 to 1000 fold greater than for other HDACs. In other embodiments, the compound has a selectivity for each of HDAC1, HDAC2, and/or HDAC6 when tested in a HDAC enzyme assay, of about 5 to 1000 fold greater than for other HDACs.

In another aspect, provided herein is a method of treating a disease mediated by one or more HDACs in a subject comprising administering to the subject in need thereof a compound of Formula I, Formula II, Formula III, or any of the compounds presented in Table 1, or pharmaceutically acceptable salts thereof. In some embodiments, the disease is mediated by HDAC1 and/or HDAC2. In other embodiments, the disease is mediated by HDAC6. In other embodiments, the disease is mediated by HDAC1 and/or HDAC2 and/or HDAC6.

In another aspect, provided herein is a method of treating a disease in a subject comprising administering to the subject a compound of Formula I, Formula II, Formula III, or any of the compounds presented in Table 1, or a pharmaceutically acceptable salt thereof. In an embodiment, the disease is a hemoglobinopathy. In another embodiment, the disease is sickle-cell disease. In yet another embodiment, the disease is beta-thalassemia.

In a further embodiment, the disease is a neurodegenerative disease. The neurodegenerative disease can be selected from a group consisting of Alzheimer's disease, frontotemporal lobe dementia, progressive supranuclear palsy, corticobasal dementia, Parkinson's disease, Huntington's disease, amytrophic lateral sclerosis, Charcot-Marie-Tooth disease and peripheral neuropathy.

In a further embodiment, the disease is a cancer or a proliferation disease. The cancer can be selected from a group consisting of lung cancer, colon and rectal cancer, breast cancer, prostate cancer, liver cancer, pancreatic cancer, brain cancer, kidney cancer, ovarian cancer, stomach cancer, skin cancer, bone cancer, gastric cancer, breast cancer, glioma, gliobastoma, neuroblastoma, hepatocellular carcinoma, papillary renal carcinoma, head and neck squamous cell carcinoma, leukemia, lymphomas, myelomas, retinoblastoma, cervical cancer, melanoma and/or skin cancer, bladder cancer, uterine cancer, testicular cancer, esophageal cancer, and solid tumors. In another embodiment, the cancer is lung cancer, colon cancer, breast cancer, neuroblastoma, leukemia, or lymphomas. In still another embodiment, the cancer is non-small cell lung cancer (NSCLC) or small cell lung cancer. In another embodiment, the cancer is a hematologic cancer. In a further embodiment, the hematologic cancer is a leukemia or lymphoma. The lymphoma can be Hodgkin's or Non Hodgkin's lymphoma.

Provided in some embodiments are methods for inhibiting migration of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof. The HDAC1, HDAC2, and/or HDAC6 selective inhibitor can be any compound selected from the group consisting of a compound of Formula I, Formula II, Formula III, any of the compounds presented in Table 1, Compound X, and Compound Y.

Provided in some embodiments are methods for inducing maturation of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof. The HDAC1, HDAC2, and/or HDAC6 selective inhibitor can be any compound selected from the group consisting of a compound of Formula I, Formula II, Formula III, any of the compounds presented in Table 1, Compound X, and Compound Y.

Provided in some embodiments are methods for altering cell cycle progression of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof. The HDAC1, HDAC2, and/or HDAC6 selective inhibitor can be any compound selected from the group consisting of a compound of Formula I, Formula II, Formula III, any of the compounds presented in Table 1, Compound X, and Compound Y.

Provided in some embodiments are methods for decreasing viability and survival of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof. The HDAC1, HDAC2, and/or HDAC6 selective inhibitor can be any compound selected from the group consisting of a compound of Formula I, Formula II, Formula III, any of the compounds presented in Table 1, Compound X, and Compound Y.

Provided in some embodiments are methods for inducing differentiation of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof. The HDAC1, HDAC2, and/or HDAC6 selective inhibitor can be any compound selected from the group consisting of a compound of Formula I, Formula II, Formula III, any of the compounds presented in Table 1, Compound X, and Compound Y.

Provided in some embodiments are methods for enhancing low-concentration ATRA treatment of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof. The HDAC1, HDAC2, and/or HDAC6 selective inhibitor can be any compound selected from the group consisting of a compound of Formula I, Formula II, Formula III, any of the compounds presented in Table 1, Compound X, and Compound Y.

Provided in some embodiments are methods for inducing cell cycle arrest of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof. The HDAC1, HDAC2, and/or HDAC6 selective inhibitor can be any compound selected from the group consisting of a compound of Formula I, Formula II, Formula III, any of the compounds presented in Table 1, Compound X, and Compound Y.

Provided in some embodiments are methods for treating neuroblastoma in a subject comprising administering to the subject a therapeutically effective amount of Compound 001, Compound X, or Compound Y.

In a further embodiment of the methods of treatment described herein, the subject to be treated is a human.

Other objects, features, and advantages will become apparent from the following detailed description. The detailed description and specific examples are given for illustration only because various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. Further, the examples demonstrate the principle of the invention.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a graph showing fetal globin induction (% HbG mRNA) upon administering Compound 001 at 1, 5, and 10 μM.

FIGS. 2A-F: Compound 001 and MS-275 (Entinostat) were tested for their effects on human erythroid, myeloid and megakaryocyte hematopoietic progenitor proliferation in media formulations containing various cytokines. Left panels show the concentration of 50% inhibition of colony growth (IC₅₀) for each compound. Right panels show the number absolute number of colonies per plate in each assay were plotted for solvent control (DMSO) or indicated compounds at 1 μM.

FIG. 3A shows dose-response curves for Compound 001 at Day 0, Day 3, Day 5, and Day 7, with the half-maximal dose (IC₅₀) at each day indicated by a dashed line.

FIG. 3B shows the relative growth of H929 cells over time in the absence of drug as well as in the presence of increasing doses of Compound 001. The dashed line indicates the level of viability at Day 0, thus doses over 3 uM resulted in a net decrease in the viability of H929 cells.

FIGS. 4A-C are a set of graphs that show the results of migration assays in neuroblastoma cells. FIG. 4A is a graph that shows normalized migration data (OD 570) of SK-N-SH neuroblastoma cells, normalized to CTG data. FIG. 4B is a graph that shows normalized migration data (cell count) for SK-N-SH neuroblastoma cells, normalized to CTG data. FIG. 4C is a graph that shows SK-N-SH neuroblastoma cells (CTG normalized to DMSO). Compound 001 was given at various concentrations. Gefitinib is an EGFR inhibitor. EGF was used to stimulate cancer cell migration.

FIGS. 5A-C are a set of graphs that show the fold change of genes associated with maturation in BE(2)-C neuroblastoma cells upon treatment for 4 days with Compound X at 0.5 μM (FIG. 5A), 1 μM (FIG. 5B), and 3 μM (FIG. 5C).

FIG. 5D shows the results of a positive control experiment in which BE(2)-C neuroblastoma cells were treated for 4 days with 1 μM ATRA (all trans retinoic acid).

FIG. 5E shows the results of a negative control experiment in which BE(2)-C neuroblastoma cells were treated for 4 days with 1 μM of a HDAC6 selective inhibitor.

FIGS. 6A-D are a set of graphs that show the fold change of genes associated with maturation in SH-SY5Y neuroblastoma cells upon treatment for 72 hours with 1 μM of ATRA (all trans retinoic acid) (FIG. 6A), a HDAC6 selective inhibitor (FIG. 6B), Compound X (FIG. 6C), and another HDAC6 selective inhibitor (FIG. 6D).

FIGS. 7A-D are a set of graphs that show the fold change of genes associated with maturation in BE(2)-C neuroblastoma cells upon treatment for 72 hours with 1 μM of ATRA (all trans retinoic acid) (FIG. 7A), a HDAC6 selective inhibitor (FIG. 7B), Compound X (FIG. 7C), and another HDAC6 selective inhibitor (FIG. 7D).

FIGS. 8A-C are a set of graphs that show the fold change of genes associated with maturation. FIG. 8A is a graph that shows the fold change of genes associated with maturation in BE(2)-C neuroblastoma cells upon treatment for 2 days with 3 μM Compound 001. FIG. 8B is a graph that shows the fold change of genes associated with maturation in SH-SY5Y neuroblastoma cells upon treatment for 2 days with 3 μM Compound 001. FIG. 8C is a graph that shows the fold change of genes associated with maturation in BE(2)-C neuroblastoma cells upon treatment for 2 days with 3 μM Compound X.

FIGS. 9A-C are a set of graphs that show the fold change of genes associated with maturation in BE(2)-C neuroblastoma cells upon treatment for 48 hours with Compound 001 at 0.5 μM (FIG. 9A), 2 μM (FIG. 9B), and 4 μM (FIG. 9C).

FIG. 9D is a graph that shows the results of a positive control experiment in which BE(2)-C neuroblastoma cells were treated for 48 hours with 1 μM ATRA (all trans retinoic acid).

FIGS. 10A-C are a set of graphs that show the fold change of genes associated with maturation in BE(2)-C neuroblastoma cells upon treatment for 4 days with a HDAC3 selective inhibitor at 1 μM (FIG. 10A), 0.5 μM (FIG. 10B), and 3 μM (FIG. 10C).

FIG. 10D shows the results of a positive control experiment in which BE(2)-C neuroblastoma cells were treated for 4 days with 1 μM ATRA (all trans retinoic acid).

FIG. 10E shows the results of a negative control experiment in which BE(2)-C neuroblastoma cells were treated for 4 days with 1 μM of a HDAC6 selective inhibitor.

FIGS. 11A-C are a set of graphs that show the fold change of genes associated with maturation in BE(2)-C neuroblastoma cells upon treatment for 48 hours with a HDAC6 selective inhibitor at 0.5 μM (FIG. 11A), 2 μM (FIG. 11B), and 4 μM (FIG. 11C).

FIG. 11D shows the results of a positive control experiment in which BE(2)-C neuroblastoma cells were treated for 48 hours with 1 μM ATRA (all trans retinoic acid).

FIGS. 12A-D are a set of graphs that show that selective HDAC inhibitors alter cell cycle progression in neuroblastoma cells. FIG. 12A is a graph that shows the treatment of SH-SY5Y neuroblastoma cells for 72 hours with 0, 0.5, 2, and 5 μM of a HDAC6 selective inhibitor. FIG. 12B is a graph that shows the treatment of SH-SY5Y neuroblastoma cells for 72 hours with 0, 0.5, 2, and 5 μM Compound X. FIG. 12C is a graph that shows the treatment of SH-SY5Y neuroblastoma cells for 72 hours with 0, 0.5, 2, and 5 μM Compound 001. FIG. 12D is a graph that shows the treatment of SH-SY5Y neuroblastoma cells for 72 hours with 0 and 1 μM ATRA (all trans retinoic acid).

FIGS. 13A-D are a set of graphs that show that selective HDAC inhibitors decrease neuroblastoma viability and survival. FIG. 13A is a graph that shows the treatment of SK-N-BE(2) neuroblastoma cells with varying concentrations of Compound Y. Viability and the Caspase 3/7 Signal were measured at 48 hours. FIG. 13B is a graph that shows the treatment of SK-N-BE(2) neuroblastoma cells with varying concentrations of Compound X. Viability and the Caspase 3/7 Signal were measured at 48 hours. FIG. 13C is a graph that shows the treatment of SH-SY5Y neuroblastoma cells with varying concentrations of Compound Y. Viability and the Caspase 3/7 Signal were measured at 48 hours. FIG. 13D is a graph that shows the treatment of SH-SY5Y neuroblastoma cells with varying concentrations of Compound X. Viability and the Caspase 3/7 Signal were measured at 48 hours.

FIGS. 14A-D are a set of graphs that show that selective HDAC inhibitors decrease neuroblastoma viability and survival. FIG. 14A is a graph that shows the percentage of the population of SK-N-BE2 neuroblastoma cells at various stages of the cell cycle 96 hours after treatment with varying concentrations of Compound Y. FIG. 14B is a graph that shows the percentage of the population of SK-N-BE2 neuroblastoma cells at various stages of the cell cycle 96 hours after treatment with varying concentrations of Compound X. FIG. 14C is a graph that shows the percentage of the population of SH-SY5Y neuroblastoma cells at various stages of the cell cycle 96 hours after treatment with varying concentrations of Compound Y. FIG. 14D is a graph that shows the percentage of the population of SH-SY5Y neuroblastoma cells at various stages of the cell cycle 96 hours after treatment with varying concentrations of Compound X.

FIGS. 15A-D are a set of graphs that show that selective HDAC inhibitors drive neuroblastoma cells to differentiate. FIG. 15A is a graph that shows the differentiation index for SK-N-BE2 cells that were treated with varying concentrations of Compound X and/or ATRA. FIG. 15B is a graph that shows the differentiation index for SH-SY5Y cells that were treated with varying concentrations of Compound X and/or ATRA. FIG. 15C is a graph that shows the differentiation index for SK-N-BE2 cells that were treated with varying concentrations of Compound Y and/or ATRA. FIG. 15D is a graph that shows the differentiation index for SH-SY5Y cells that were treated with varying concentrations of Compound Y and/or ATRA.

FIGS. 16A-C are a set of graphs that show that selective HDAC inhibitors enhance low-concentration ATRA. FIG. 16A is a graph that shows the differentiation index for SK-N-BE(2) and SH-SY5Y neuroblastoma cells that were treated with varying concentrations of ATRA. FIG. 16B is a graph that shows the differentiation index for SK-N-BE(2) neuroblastoma cells that were treated with varying concentrations of Compound Y and/or ATRA. FIG. 16C is a graph that shows the differentiation index for SK-N-BE(2) neuroblastoma cells that were treated with varying concentrations of Compound X and/or ATRA.

FIGS. 17A-D are a set of graphs that show that selective HDAC inhibitors induce cell cycle arrest in neuroblastoma cells. FIG. 17A is a graph that shows the percentage of the population of SK-N-BE(2) neuroblastoma cells at various stages of the cell cycle 4 days after treatment with varying concentrations of Compound Y and/or ATRA. FIG. 17B is a graph that shows the percentage of the population of SK-N-BE(2) neuroblastoma cells at various stages of the cell cycle 4 days after treatment with varying concentrations of Compound X and/or ATRA. FIG. 17C is a graph that shows the fold change of p21 in SK-N-BE(2) cells 4 days after treatment with varying concentrations of Compound Y and/or ATRA. FIG. 17D is a graph that shows the fold change of p21 in SK-N-BE(2) cells 4 days after treatment with varying concentrations of Compound X and/or ATRA.

FIGS. 18A-D are a set of graphs that show that selective HDAC inhibitors induce cell cycle arrest in neuroblastoma cells. FIG. 18A is a graph that shows the percentage of the population of SH-SY5Y neuroblastoma cells at various stages of the cell cycle 4 days after treatment with varying concentrations of Compound Y and/or ATRA. FIG. 18B is a graph that shows the percentage of the population of SH-SY5Y neuroblastoma cells at various stages of the cell cycle 4 days after treatment with varying concentrations of Compound X and/or ATRA. FIG. 18C is a graph that shows the fold change of p21 in SH-SY5Y cells 4 days after treatment with varying concentrations of Compound Y and/or ATRA. FIG. 18D is a graph that shows the fold change of p21 in SH-SY5Y cells 4 days after treatment with varying concentrations of Compound X and/or ATRA.

DETAILED DESCRIPTION

The instant application is directed, generally, to compounds, pharmaceutical compositions comprising such compounds, and methods of using such compounds to treat or prevent diseases or disorders associated with HDAC activity, particularly diseases or disorders that involve any type of HDAC1, HDAC2, or HDAC6 expression. Such diseases include, but are not limited to, cancer, neurodegenerative disease, sickle-cell anemia, and beta-thalassemia.

Inhibition of HDAC1 and HDAC2 has been shown to derepress fetal globin. Fetal hemoglobin (HbF) derepression, or induction, is an established therapeutic strategy in sickle cell disease, and could also be effective in treating beta-thalassemia. Hydroxyurea is currently the only drug with proven efficacy in sickle cell disease (SCD). This therapy is cytotoxic, poorly tolerated, and only reduces the frequency and severity of sickle cell crises in a subset of patients. There are no approved drugs for the treatment of beta-thalassemia. Fetal (γ) globin expression is silenced in adults partly through the action of a complex containing BCL11A and HDACs 1 and 2. Genetic ablation and chemical inhibition of HDAC1 or HDAC2 results in the derepression of γ globin in adult bone marrow derived erythroid cells (Bradner, Proc Natl Acad Sci 2010). While a variety of non-specific HDAC inhibitors have been used successfully to induce HbF, further clinical development has been limited by their variable efficacy and concerns over off target side-effects observed in small clinical trials. Therefore, development of selective and potent HDAC1 and HDAC2 inhibitors leading to HbF reactivation represents a refined and more targeted therapeutic approach for the treatment of SCD and beta-thalassemia.

It has also been shown that HDAC2 expression and activity are elevated in neurodegenerative diseases (Guan, 2009; Morris, 2013). Increasing the expression of HDAC2 impairs cognitive function in mice. Inhibition of HDAC2 by gene disruption restores cognitive function in mouse models of Alzheimer's disease (Guan, 2009; Morris, 2013; Graff, 2014). In addition, the activity of HDAC6 is implicated in neurodegenerative diseases (Xiong, 2013; Simoes-Peres, 2013; Kim, 2012). Combined inhibition of HDAC2 and HDAC6 could have a more profound effect on the development of neurodegenerative diseases than inhibition of either enzyme alone.

It has also been shown that deregulated HDAC1 expression is particularly common in advanced cancers of the gastrointestinal system, such as, for example, pancreatic, colorectal, and liver (hepatocellular) carcinomas, as well as in prostate and breast cancer. HDAC2 and HDAC3 expression are also associated with advanced stage disease and poor prognosis in gastric, prostate and colorectal cancers. HDAC2 is also over expressed in cervical cancer. Clinical trials for the treatment of patients with advanced solid tumors, lymphomas, and leukemias utilizing class I selective HDAC inhibitors such as MS275, depsipeptide, and MGCD0103 have been published (O. Witt et al., Cancer Letters, 2009, 277, 8-21 and H-J. Kim and S.-C. Bae, Am. J. Transl. Res. 2011; 3(2): 166-179). HDACs have also been found to repress HIV-1 (Human Immunodeficiency Virus) transcription through deacetylation events, particularly in latently infected resting CD4+ T cells.

As such, it is known that HDAC inhibitors can induce the transcriptional activation of the HIV-1 promoter, or re-activate latent HIV-1 from the patient viral reservoir. It is generally accepted that the use of HDAC inhibitors in the treatment of HIV infection can be valuable in purging the latently infected reservoirs in patients, particularly patients undergoing Highly Active Antiretroviral Therapy (HAAT).

The compounds described herein have HDAC1 IC₅₀ values ranging from 1 to 2000 nM and HDAC2 IC₅₀ values ranging from 10 to 3000 nM, demonstrating approximately 2- to 100-fold selectivity over HDAC3, respectively.

The compounds described herein have HDAC6 IC₅₀ values ranging from 1 to 20 nM, demonstrating approximately 5- to 1000-fold selectivity than for other HDACs.

DEFINITIONS

Listed below are definitions of various terms used to describe this invention. These definitions apply to the terms as they are used throughout this specification and claims, unless otherwise limited in specific instances, either individually or as part of a larger group.

The number of carbon atoms in an alkyl substituent can be indicated by the prefix “C_(x-y),” where x is the minimum and y is the maximum number of carbon atoms in the substituent. Likewise, a C_(x) chain means an alkyl chain containing x carbon atoms.

The term “about” generally indicates a possible variation of no more than 10%, 5%, or 1% of a value. For example, “about 25 mg/kg” will generally indicate, in its broadest sense, a value of 22.5-27.5 mg/kg, i.e., 25±2.5 mg/kg.

The term “alkyl” refers to saturated, straight- or branched-chain hydrocarbon moieties containing, in certain embodiments, between one and six, or one and eight carbon atoms, respectively. Examples of C₁₋₆-alkyl moieties include, but are not limited to, methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, neopentyl, n-hexyl moieties; and examples of C₁₋₈-alkyl moieties include, but are not limited to, methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, neopentyl, n-hexyl, heptyl, and octyl moieties.

The term “alkenyl” denotes a monovalent group derived from a hydrocarbon moiety containing, in certain embodiments, from two to six, or two to eight carbon atoms having at least one carbon-carbon double bond. The double bond may or may not be the point of attachment to another group. Alkenyl groups include, but are not limited to, for example, ethenyl, propenyl, butenyl, 1-methyl-2-buten-1-yl, heptenyl, octenyl and the like.

The term “alkynyl” denotes a monovalent group derived from a hydrocarbon moiety containing, in certain embodiments, from two to six, or two to eight carbon atoms having at least one carbon-carbon triple bond. The alkynyl group may or may not be the point of attachment to another group. Representative alkynyl groups include, but are not limited to, for example, ethynyl, 1-propynyl, 1-butynyl, heptynyl, octynyl and the like.

The term “alkoxy” refers to an —O-alkyl moiety.

The term “aryl” refers to a mono- or poly-cyclic carbocyclic ring system having one or more aromatic rings, fused or non-fused, including, but not limited to, phenyl, naphthyl, tetrahydronaphthyl, indanyl, idenyl, and the like. In some embodiments, aryl groups have 6 carbon atoms. In some embodiments, aryl groups have from six to ten carbon atoms. In some embodiments, aryl groups have from six to sixteen carbon atoms.

The term “cycloalkyl” denotes a monovalent group derived from a monocyclic or polycyclic saturated or partially unsaturated carbocyclic ring compound. Examples of C₃₋₈-cycloalkyl include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclopentyl and cyclooctyl; and examples of C₃₋₁₂-cycloalkyl include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, bicyclo[2.2.1]heptyl, and bicyclo[2.2.2]octyl. Also contemplated are monovalent groups derived from a monocyclic or polycyclic carbocyclic ring compound having at least one carbon-carbon double bond by the removal of a single hydrogen atom. Examples of such groups include, but are not limited to, cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclooctenyl, and the like.

The term “heteroaryl” refers to a mono- or poly-cyclic (e.g., bi-, or tri-cyclic or more) fused or non-fused moiety or ring system having at least one aromatic ring, where one or more of the ring-forming atoms is a heteroatom such as oxygen, sulfur, or nitrogen. In some embodiments, the heteroaryl group has from one to six carbon atoms, and in further embodiments from one to fifteen carbon atoms. In some embodiments, the heteroaryl group contains five to sixteen ring atoms of which one ring atom is selected from oxygen, sulfur, and nitrogen; zero, one, two, or three ring atoms are additional heteroatoms independently selected from oxygen, sulfur, and nitrogen; and the remaining ring atoms are carbon. Heteroaryl includes, but is not limited to, pyridinyl, pyrazinyl, pyrimidinyl, pyrrolyl, pyrazolyl, imidazolyl, thiazolyl, oxazolyl, isooxazolyl, thiazolyl, thiadiazolyl, oxadiazolyl, thiophenyl, furanyl, indolyl, quinolinyl, isoquinolinyl, benzimidazolyl, benzooxazolyl, quinoxalinyl, acridinyl, and the like.

The term “heterocycloalkyl” refers to a non-aromatic 3-, 4-, 5-, 6- or 7-membered ring or a bi- or tri-cyclic group fused of non-fused system, where (i) each ring contains between one and three heteroatoms independently selected from oxygen, sulfur, and nitrogen, (ii) each 5-membered ring has 0 to 1 double bonds and each 6-membered ring has 0 to 2 double bonds, (iii) the nitrogen and sulfur heteroatoms may optionally be oxidized, (iv) the nitrogen heteroatom may optionally be quaternized, and (iv) any of the above rings may be fused to a benzene ring. Representative heterocycloalkyl groups include, but are not limited to, [1,3]dioxolane, pyrrolidinyl, pyrazolinyl, pyrazolidinyl, imidazolinyl, imidazolidinyl, piperidinyl, piperazinyl, oxazolidinyl, isoxazolidinyl, morpholinyl, thiazolidinyl, isothiazolidinyl, and tetrahydrofuryl.

In accordance with the invention, any of the aryls, substituted aryls, heteroaryls and substituted heteroaryls described herein, can be any aromatic group.

The terms “halo” and “halogen” refer to an atom selected from fluorine, chlorine, bromine, and iodine.

The term “haloalkyl” refers to alkl radicals wherein any one or more of the alkyl carbon atoms is substituted with halo as defined above. Haloalkyl also embraces monohaloalkyl, dihaloalkyl, and polyhaloalkyl radicals. Examples of haloalkyl include, but are not limited to, fluoromethyl, difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl, trichloromethyl, and pentafluoroethyl.

The term “HDAC” refers to histone deacetylases, which are enzymes that remove the acetyl groups from the lysine residues in core histones, thus leading to the formation of a condensed and transcriptionally silenced chromatin. There are currently 18 known histone deacetylases, which are classified into four groups. Class I HDACs, which include HDAC1, HDAC2, HDAC3, and HDAC8, are related to the yeast RPD3 gene. Class II HDACs, which include HDAC4, HDAC5, HDAC6, HDAC7, HDAC9, and HDAC10, are related to the yeast Hda1 gene. Class III HDACs, which are also known as the sirtuins are related to the Sir2 gene and include SIRT1-7. Class IV HDACs, which contains only HDAC11, has features of both Class I and II HDACs. The term “HDAC” refers to any one or more of the 18 known histone deacetylases, unless otherwise specified.

The term “inhibitor” is synonymous with the term antagonist.

The terms “isolated,” “purified,” or “biologically pure” refer to material that is substantially or essentially free from components that normally accompany it as found in its native state. Purity and homogeneity are typically determined using analytical chemistry techniques such as polyacrylamide gel electrophoresis or high performance liquid chromatography. Particularly, in embodiments the compound is at least 85% pure, more preferably at least 90% pure, more preferably at least 95% pure, and most preferably at least 99% pure.

The term “pharmaceutically acceptable salt” refers to those salts of the compounds formed by the process of the present invention which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of humans and lower animals without undue toxicity, irritation, allergic response and the like, and are commensurate with a reasonable benefit/risk ratio. Additionally, “pharmaceutically acceptable salts” refers to derivatives of the disclosed compounds wherein the parent compound is modified by converting an existing acid or base moiety to its salt form. Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as carboxylic acids; and the like. The pharmaceutically acceptable salts of the present invention include the conventional non-toxic salts of the parent compound formed, for example, from non-toxic inorganic or organic acids. The pharmaceutically acceptable salts of the present invention can be synthesized from the parent compound which contains a basic or acidic moiety by conventional chemical methods. Generally, such salts can be prepared by reacting the free acid or base forms of these compounds with a stoichiometric amount of the appropriate base or acid in water or in an organic solvent, or in a mixture of the two; generally, nonaqueous media like ether, ethyl acetate, ethanol, isopropanol, or acetonitrile are preferred. Lists of suitable salts are found in Remington's Pharmaceutical Sciences, 17^(th) ed., Mack Publishing Company, Easton, Pa., 1985, p. 1418 and Journal of Pharmaceutical Science, 66, 2 (1977), each of which is incorporated herein by reference in its entirety.

Combinations of substituents and variables envisioned by this invention are only those that result in the formation of stable compounds. The term “stable” refers to compounds which possess stability sufficient to allow manufacture and which maintains the integrity of the compound for a sufficient period of time to be useful for the purposes detailed herein (e.g., therapeutic or prophylactic administration to a subject).

The term “subject” refers to a mammal. A subject therefore refers to, for example, dogs, cats, horses, cows, pigs, guinea pigs, and the like. Preferably the subject is a human. When the subject is a human, the subject may be referred to herein as a patient.

The terms “treat”, “treating” and “treatment” refer to a method of alleviating or abating a disease and/or its attendant symptoms.

Compounds of the Invention

In one aspect, the invention provides a compound of Formula I:

or a pharmaceutically acceptable salt thereof, wherein,

R_(x) is selected from the group consisting of C₁₋₆-alkyl, C₁₋₆-alkoxy, halo, —OH, —C(O)R¹, —CO₂R¹, —C(O)N(R¹)₂, aryl, —C(S)N(R¹)₂, and S(O)₂R¹, wherein aryl may be optionally substituted by one or more groups selected from C₁₋₆-alkyl, C₁₋₆-alkoxy, —OH, halo, and haloalkyl;

R_(y) is selected from the group consisting of H, C₁₋₆-alkyl, C₁₋₆-alkoxy, halo, —OH, —C(O)R¹, —CO₂R¹, and —C(O)N(R¹)₂;

R_(z) is selected from the group consisting of C₁₋₆-alkyl, C₁₋₆-alkenyl, C₁₋₆-alkynyl, C₃₋₈-cycloalkyl, C₃₋₇-heterocycloalkyl, aryl, and heteroaryl, each of which may be optionally substituted by C₁₋₆-alkyl, C₁₋₆-alkoxy, halo, or —OH; and

each R¹ is, independently for each occurrence, selected from the group consisting of H, C₁₋₆-alkyl, C₃₋₈-cycloalkyl, C₃₋₇-heterocycloalkyl, aryl, heteroaryl, C₁₋₆-alkyl-cyclo alkyl, C₁₋₆-alkyl-heterocycloalkyl, C₁₋₆-alkyl-aryl, and C₁₋₆-alkyl-heteroaryl, wherein C₃₋₈-cyclo alkyl, C₃₋₇-heterocycloalkyl, aryl, heteroaryl, C₁₋₆-alkyl-cyclo alkyl, C₁₋₆-alkyl-heterocycloalkyl, C₁₋₆-alkyl-aryl, and C₁₋₆-alkyl-heteroaryl may be optionally substituted by one or more groups selected from C₁₋₆-alkyl, C₁₋₆-alkoxy, —OH, halo, and haloalkyl.

In an embodiment of the compound of Formula I or a pharmaceutically acceptable salt thereof,

R_(x) is selected from the group consisting of C₁₋₆-alkyl, C₁₋₆-alkoxy, halo, —OH, —C(O)R¹, —CO₂R¹, and —C(O)N(R¹)₂;

R_(y) is selected from the group consisting of H, C₁₋₆-alkyl, C₁₋₆-alkoxy, halo, —OH, —C(O)R¹, —CO₂R¹, and —C(O)N(R¹)₂;

R_(z) is selected from the group consisting of C₁₋₆-alkyl, C₁₋₆-alkenyl, C₁₋₆-alkynyl, C₃₋₈-cycloalkyl, C₃₋₇-heterocycloalkyl, aryl, and heteroaryl, each of which may be optionally substituted by C₁₋₆-alkyl, C₁₋₆-alkoxy, halo, or —OH; and

each R¹ is, independently for each occurrence, selected from the group consisting of H, C₁₋₆-alkyl, C₃₋₈-cycloalkyl, C₃₋₇-heterocycloalkyl, aryl, heteroaryl, C₁₋₆-alkyl-cyclo alkyl, C₁₋₆-alkyl-heterocycloalkyl, C₁₋₆-alkyl-aryl, and C₁₋₆-alkyl-heteroaryl.

In one embodiment of the compound of Formula I, provided herein is a compound of Formula II:

or a pharmaceutically acceptable salt thereof,

wherein,

R_(x) is independently selected from the group consisting of aryl, —C(O)R¹, —CO₂R¹, —C(O)N(R¹)₂, —C(S)N(R¹)₂, and S(O)₂R¹;

R_(y) is selected from the group consisting of H, C₁₋₆-alkyl, and halo; and

R_(z) is selected from the group consisting of C₁₋₆-alkyl, C₃₋₈-cycloalkyl, C₃₋₇-heterocycloalkyl, aryl, and heteroaryl.

In one embodiment of the compound of Formula II, or a pharmaceutically acceptable salt thereof, R_(x) is independently selected from the group consisting of —C(O)R¹, —CO₂R¹, and —C(O)N(R¹)₂; and R_(z) is selected from the group consisting of C₁₋₆-alkyl, C₃₋₈-cycloalkyl, C₃₋₇-heterocycloalkyl, aryl, and heteroaryl.

In an embodiment of the compounds of Formula I or II, R_(z) is C₁₋₆-alkyl or aryl. In preferred embodiments of the compounds of Formula I or II, R_(z) is isopropyl or phenyl. In another embodiment of the compounds of Formula I or II, R_(z) is methyl.

In another embodiment of the compounds of Formula I or II, R_(x) is —C(O)N(R¹)₂ or —C(O)NHR¹. In yet another embodiment of the compounds of Formula I or II, R_(x) is —C(O)R¹ or —CO₂R¹. In yet another embodiment of the compounds of Formula I or II, R_(x) is —C(S)N(R¹)₂, —C(S)NHR¹, or S(O)₂R¹.

In an embodiment of the compounds of Formula I or II, at least one of R¹ is selected from the group consisting of C₁₋₆-alkyl, aryl, C₁₋₆-alkyl-aryl and C₁₋₆-alkyl-heteroaryl, wherein aryl, C₁₋₆-alkyl-aryl and C₁₋₆-alkyl-heteroaryl may be optionally substituted by one or more groups selected from C₁₋₆-alkyl, C₁₋₆-alkoxy, —OH, halo, and haloalkyl. In a further embodiment, R¹ is —CH₃, —CH₂CH₃, phenyl, —CH₂-phenyl, or —CH₂-indolyl, wherein phenyl, —CH₂-phenyl, or —CH₂— indolyl may be optionally substituted by one or more groups selected from C₁₋₆-alkyl and halo.

In another embodiment of the compounds of Formula I or II, at least one of R¹ is, independently for each occurrence, selected from the group consisting of C₁₋₆-alkyl, aryl, and C₁₋₆-alkyl-aryl. In a further embodiment, at least one of R¹ may be —CH₃, —CH₂CH₃, —CH₂-phenyl, or phenyl.

In another embodiment of the compounds of Formulas I or II, at least one of R¹ is phenyl, wherein phenyl is optionally substituted by one or more groups selected from C₁₋₆-alkyl, C₁₋₆-alkoxy, halo, and haloalkyl. In preferred embodiments, at least one of R¹ is phenyl, wherein phenyl is optionally substituted by one or more groups selected from CH₃, —OCH₃, fluoro, chloro, and CF₃.

In yet another preferred embodiment of the compounds of Formula I or II, R_(y) is H.

In another embodiment of the compounds of Formula I or II, R_(x) is —C(O)R¹; and

R¹ is C₁₋₆-alkyl, C₁₋₆-alkyl-aryl or C₁₋₆-alkyl-heteroaryl, wherein C₁₋₆-alkyl-aryl or C₁₋₆-alkyl-heteroaryl may be optionally substituted by one or more groups selected from C₁₋₆-alkyl, C₁₋₆-alkoxy, —OH, halo, and haloalkyl. In a preferred embodiment, R¹ is CH₂-phenyl or CH₂-indolyl, wherein CH₂-phenyl or CH₂-indolyl may be optionally substituted by one or more groups selected from C₁₋₆-alkyl and halo.

In another embodiment of the compound of Formula I, provided herein is a compound of Formula III:

or a pharmaceutically acceptable salt thereof,

wherein,

R_(x) is selected from the group consisting of aryl, —C(O)R¹, —CO₂R¹, —C(O)N(R¹)₂, —C(S)N(R¹)₂, and S(O)₂R¹, wherein aryl may be optionally substituted by one or more groups selected from C₁₋₆-alkyl, C₁₋₆-alkoxy, —OH, halo, and haloalkyl; and

each R¹ is, independently for each occurrence, selected from the group consisting of H, C₁₋₆-alkyl, C₃₋₈-cycloalkyl, C₃₋₇-heterocycloalkyl, aryl, heteroaryl, C₁₋₆-alkyl-cyclo alkyl, C₁₋₆-alkyl-heterocycloalkyl, C₁₋₆-alkyl-aryl, and C₁₋₆-alkyl-heteroaryl, wherein C₁₋₆-alkyl, C₃₋₈-cycloalkyl, C₃₋₇-heterocycloalkyl, aryl, heteroaryl, C₁₋₆-alkyl-cycloalkyl, C₁₋₆-alkyl-heterocycloalkyl, C₁₋₆-alkyl-aryl, and C₁₋₆-alkyl-heteroaryl may be optionally substituted by one or more groups selected from C₁₋₆-alkyl, C₁₋₆-alkoxy, halo, and haloalkyl.

In an embodiment of the compounds of Formula III, R_(x) is —C(O)NHR¹, —C(S)NHR¹, or S(O)₂R¹; and

R¹ is, independently for each occurrence, selected from the group consisting of C₁₋₆-alkyl, C₃₋₈-cycloalkyl, C₃₋₇-heterocycloalkyl, aryl, heteroaryl, C₁₋₆-alkyl-cycloalkyl, C₁₋₆-alkyl-heterocycloalkyl, C₁₋₆-alkyl-aryl, and C₁₋₆-alkyl-heteroaryl, wherein C₃₋₈-cycloalkyl, C₃₋₇-heterocycloalkyl, aryl, and heteroaryl may be optionally substituted by one or more groups selected from C₁₋₆-alkyl, C₁₋₆-alkoxy, —OH, halo, and haloalkyl.

In another embodiment of the compounds of Formula III, at least one of R¹ is selected from the group consisting of C₁₋₆-alkyl, aryl, heteroaryl, C₁₋₆-alkyl-aryl, and C₁₋₆-alkyl-heteroaryl, wherein aryl may be optionally substituted by one or more groups selected from C₁₋₆-alkyl, C₁₋₆-alkoxy, —OH, halo, and haloalkyl.

In another embodiment of the compounds of Formula III, at least one of R¹ is aryl, wherein aryl is optionally substituted by one or more groups selected from C₁₋₆-alkyl, C₁₋₆-alkoxy, halo, and haloalkyl.

In a preferred embodiment of the compounds of Formula III, at least one of R¹ is phenyl, wherein phenyl is optionally substituted by one or more groups selected from CH₃, —OCH₃, fluoro, chloro, and CF₃.

In another embodiment of the compounds of Formula III, R_(x) is —C(O)R¹; and

R¹ is C₁₋₆-alkyl, C₁₋₆-alkyl-aryl or C₁₋₆-alkyl-heteroaryl, wherein C₁₋₆-alkyl-aryl or C₁₋₆-alkyl-heteroaryl may be optionally substituted by one or more groups selected from C₁₋₆-alkyl, C₁₋₆-alkoxy, —OH, halo, and haloalkyl. In a preferred embodiment, R¹ is CH₂-phenyl or CH₂-indole, wherein CH₂-phenyl or CH₂-indole may be optionally substituted by one or more groups selected from C₁₋₆-alkyl or halo.

Representative compounds of Formulas I, II, and III include, but are not limited to the following compounds of Table 1:

TABLE 1 IC₅₀, nM ID Structure HDAC1 HDAC2 HDAC3 HDAC6 001

38 34 1010 1.9 002

1010 983 1642 2.6 003

346 254 840 1.6 004

275 321 1003 2.9 005

1828 2387 8180 5.9 006

697 809 3781 4 007

119 121 879 5.1 008

21 24 546 1.5 009

356 380 1785 2.1 010

18 27 824 1.7 011

110 177 2164 14 012

266 377 1624 2.2 013

50 74 1081 2.5 014

33 43 1072 2.0 015

34 46 693 2.0 016

170 207 987 1.7 017

5.9 5.2 111 2.4 018

551 644 2485 5.1 019

854 987 3190 5.0 020

372 423 1983 4.5 021

570 642 2513 4.5 022

704 782 2703 7.3 023

844 829 3545 4.6 024

22 22 761 3.7 025

20 18 84 13 026

206 173 1100 5.0 027

130 103 422 12 028

3 2 24 2.8 029

102 93 914 11 030

23 22 114 12 031

10 9 42 5 or pharmaceutically acceptable salts thereof.

In preferred embodiments, the compounds of the instant invention have one or more of the following properties: the compound is capable of inhibiting at least one histone deacetylase (HDAC); the compound is capable of inhibiting HDAC1, HDAC2, and/or HDAC6; the compound selectively inhibits HDAC1, HDAC2 and/or HDAC6 over other HDACs.

Another object of the present invention is the use of a compound as described herein (e.g., of any formulae herein) in the manufacture of a medicament for use in the treatment of a disorder or disease herein. Another object of the present invention is the use of a compound as described herein (e.g., of any formulae herein) for use in the treatment of a disorder or disease herein.

In another aspect, the invention provides a method of synthesizing a compound of Formula I, Formula II, or any of the compounds presented in Table 1. The synthesis of the compounds of the invention can be found in the Examples below.

Another embodiment is a method of making a compound of any of the formulae herein using any one, or combination of, reactions delineated herein. The method can include the use of one or more intermediates or chemical reagents delineated herein.

Another aspect is an isotopically labeled compound of any of the formulae delineated herein. Such compounds have one or more isotope atoms which may or may not be radioactive (e.g., ³H, ²H, ¹⁴C, ¹³C, ³⁵S, ³²P, ¹²⁵I, and ¹³¹I) introduced into the compound. Such compounds are useful for drug metabolism studies and diagnostics, as well as therapeutic applications.

A compound of the invention can be prepared as a pharmaceutically acceptable acid addition salt by reacting the free base form of the compound with a pharmaceutically acceptable inorganic or organic acid. Alternatively, a pharmaceutically acceptable base addition salt of a compound of the invention can be prepared by reacting the free acid form of the compound with a pharmaceutically acceptable inorganic or organic base.

Alternatively, the salt forms of the compounds of the invention can be prepared using salts of the starting materials or intermediates.

The free acid or free base forms of the compounds of the invention can be prepared from the corresponding base addition salt or acid addition salt from, respectively. For example a compound of the invention in an acid addition salt form can be converted to the corresponding free base by treating with a suitable base (e.g., ammonium hydroxide solution, sodium hydroxide, and the like). A compound of the invention in a base addition salt form can be converted to the corresponding free acid by treating with a suitable acid (e.g., hydrochloric acid, etc.).

Protected derivatives of the compounds of the invention can be made by means known to those of ordinary skill in the art. A detailed description of techniques applicable to the creation of protecting groups and their removal can be found in T. W. Greene, “Protecting Groups in Organic Chemistry,” 3rd edition, John Wiley and Sons, Inc., 1999, and subsequent editions thereof.

Compounds of the present invention can be conveniently prepared, or formed during the process of the invention, as solvates (e.g., hydrates). Hydrates of compounds of the present invention can be conveniently prepared by recrystallization from an aqueous/organic solvent mixture, using organic solvents such as dioxan, tetrahydrofuran or methanol.

In addition, some of the compounds of this invention have one or more double bonds, or one or more asymmetric centers. Such compounds can occur as racemates, racemic mixtures, single enantiomers, individual diastereomers, diastereomeric mixtures, and cis- or trans- or E- or Z-double isomeric forms, and other stereoisomeric forms that may be defined, in terms of absolute stereochemistry, as (R)- or (S)-, or as (D)- or (L)- for amino acids. All such isomeric forms of these compounds are expressly included in the present invention. Optical isomers may be prepared from their respective optically active precursors by the procedures described above, or by resolving the racemic mixtures. The resolution can be carried out in the presence of a resolving agent, by chromatography or by repeated crystallization or by some combination of these techniques which are known to those skilled in the art. Further details regarding resolutions can be found in Jacques, et al., “Enantiomers, Racemates, and Resolutions” (John Wiley & Sons, 1981). The compounds of this invention may also be represented in multiple tautomeric forms, in such instances, the invention expressly includes all tautomeric forms of the compounds described herein. When the compounds described herein contain olefinic double bonds or other centers of geometric asymmetry, and unless specified otherwise, it is intended that the compounds include both E and Z geometric isomers. Likewise, all tautomeric forms are also intended to be included. The configuration of any carbon-carbon double bond appearing herein is selected for convenience only and is not intended to designate a particular configuration unless the text so states; thus a carbon-carbon double bond depicted arbitrarily herein as trans may be cis, trans, or a mixture of the two in any proportion. All such isomeric forms of such compounds are expressly included in the present invention. All crystal forms of the compounds described herein are expressly included in the present invention.

The synthesized compounds can be separated from a reaction mixture and further purified by a method such as column chromatography, high pressure liquid chromatography, or recrystallization. As can be appreciated by the skilled artisan, further methods of synthesizing the compounds of the formulae herein will be evident to those of ordinary skill in the art. Additionally, the various synthetic steps may be performed in an alternate sequence or order to give the desired compounds. In addition, the solvents, temperatures, reaction durations, etc. delineated herein are for purposes of illustration only and one of ordinary skill in the art will recognize that variation of the reaction conditions can produce the desired compounds of the present invention. Synthetic chemistry transformations and protecting group methodologies (protection and deprotection) useful in synthesizing the compounds described herein are known in the art and include, for example, those such as described in R. Larock, Comprehensive Organic Transformations, VCH Publishers (1989); T. W. Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis, 2d. Ed., John Wiley and Sons (1991); L. Fieser and M. Fieser, Fieser and Fieser's Reagents for Organic Synthesis, John Wiley and Sons (1994); and L. Paquette, ed., Encyclopedia of Reagents for Organic Synthesis, John Wiley and Sons (1995), and subsequent editions thereof.

The compounds of the invention are defined herein by their chemical structures and/or chemical names. Where a compound is referred to by both a chemical structure and a chemical name, and the chemical structure and chemical name conflict, the chemical structure is determinative of the compound's identity.

The recitation of a listing of chemical groups in any definition of a variable herein includes definitions of that variable as any single group or combination of listed groups. The recitation of an embodiment for a variable herein includes that embodiment as any single embodiment or in combination with any other embodiments or portions thereof.

Pharmaceutical Compositions

The invention also provides for a pharmaceutical composition comprising a compound of instant invention, or a pharmaceutically acceptable salt thereof, together with a pharmaceutically acceptable carrier.

In another aspect, the invention provides a pharmaceutical composition comprising any of the compounds of the instant invention (Formula I, Formula II, Formula III, or any of the compounds presented in Table 1) or pharmaceutically acceptable salts thereof, together with a pharmaceutically acceptable carrier.

The pharmaceutical compositions of the present invention comprise a therapeutically effective amount of a compound of the present invention formulated together with one or more pharmaceutically acceptable carriers. The term “pharmaceutically acceptable carrier” means a non-toxic, inert solid, semi-solid or liquid filler, diluent, encapsulating material or formulation auxiliary of any type. The pharmaceutical compositions of this invention can be administered to humans and other animals orally, rectally, parenterally, intracisternally, intravaginally, intraperitoneally, topically (as by powders, ointments, or drops), buccally, or as an oral or nasal spray.

Compounds of the invention can be administered as pharmaceutical compositions by any conventional route, in particular enterally, for example, orally, e.g., in the form of tablets or capsules, or parenterally, e.g., in the form of injectable solutions or suspensions, topically, e.g., in the form of lotions, gels, ointments or creams, or in a nasal or suppository form. Pharmaceutical compositions comprising a compound of the present invention in free form or in a pharmaceutically acceptable salt form in association with at least one pharmaceutically acceptable carrier or diluent can be manufactured in a conventional manner by mixing, granulating or coating methods. For example, oral compositions can be tablets or gelatin capsules comprising the active ingredient together with a) diluents, e.g., lactose, dextrose, sucrose, mannitol, sorbitol, cellulose and/or glycine; b) lubricants, e.g., silica, talcum, stearic acid, its magnesium or calcium salt and/or polyethyleneglycol; for tablets also c) binders, e.g., magnesium aluminum silicate, starch paste, gelatin, tragacanth, methylcellulose, sodium carboxymethylcellulose and or polyvinylpyrrolidone; if desired d) disintegrants, e.g., starches, agar, alginic acid or its sodium salt, or effervescent mixtures; and/or e) absorbents, colorants, flavors and sweeteners. Injectable compositions can be aqueous isotonic solutions or suspensions, and suppositories can be prepared from fatty emulsions or suspensions. The compositions may be sterilized and/or contain adjuvants, such as preserving, stabilizing, wetting or emulsifying agents, solution promoters, salts for regulating the osmotic pressure and/or buffers. In addition, they may also contain other therapeutically valuable substances. Suitable formulations for transdermal applications include an effective amount of a compound of the present invention with a carrier. A carrier can include absorbable pharmacologically acceptable solvents to assist passage through the skin of the host. For example, transdermal devices are in the form of a bandage comprising a backing member, a reservoir containing the compound optionally with carriers, optionally a rate controlling barrier to deliver the compound to the skin of the host at a controlled and predetermined rate over a prolonged period of time, and means to secure the device to the skin. Matrix transdermal formulations may also be used. Suitable formulations for topical application, e.g., to the skin and eyes, are preferably aqueous solutions, ointments, creams or gels well-known in the art. Such may contain solubilizers, stabilizers, tonicity enhancing agents, buffers and preservatives.

The active compounds can also be in micro-encapsulated form with one or more excipients as noted above. The solid dosage forms of tablets, dragees, capsules, pills, and granules can be prepared with coatings and shells such as enteric coatings, release controlling coatings and other coatings well known in the pharmaceutical formulating art. In such solid dosage forms the active compound may be admixed with at least one inert diluent such as sucrose, lactose or starch. Such dosage forms may also comprise, as is normal practice, additional substances other than inert diluents, e.g., tableting lubricants and other tableting aids such a magnesium stearate and microcrystalline cellulose. In the case of capsules, tablets and pills, the dosage forms may also comprise buffering agents.

Methods of the Invention

According to the methods of treatment of the present invention, disorders are treated or prevented in a subject, such as a human or other animal, by administering to the subject a therapeutically effective amount of a compound of the invention, in such amounts and for such time as is necessary to achieve the desired result. The term “therapeutically effective amount” of a compound of the invention means a sufficient amount of the compound so as to decrease the symptoms of a disorder in a subject. As is well understood in the medical arts, a therapeutically effective amount of a compound of this invention will be at a reasonable benefit/risk ratio applicable to any medical treatment.

In general, compounds of the invention will be administered in therapeutically effective amounts via any of the usual and acceptable modes known in the art, either singly or in combination with one or more therapeutic agents. A therapeutically effective amount may vary widely depending on the severity of the disease, the age and relative health of the subject, the potency of the compound used and other factors. In general, satisfactory results are indicated to be obtained systemically at daily dosages of from about 0.03 to 2.5 mg/kg per body weight (0.05 to 4.5 mg/m²). An indicated daily dosage in the larger mammal, e.g. humans, is in the range from about 0.5 mg to about 100 mg, conveniently administered, e.g. in divided doses up to four times a day or in retard form. Suitable unit dosage forms for oral administration comprise from ca. 1 to 50 mg active ingredient.

In certain embodiments, a therapeutic amount or dose of the compounds of the present invention may range from about 0.1 mg/kg to about 500 mg/kg (about 0.18 mg/m² to about 900 mg/m²), alternatively from about 1 to about 50 mg/kg (about 1.8 to about 90 mg/m²). In general, treatment regimens according to the present invention comprise administration to a patient in need of such treatment from about 10 mg to about 1000 mg of the compound(s) of this invention per day in single or multiple doses. Therapeutic amounts or doses will also vary depending on route of administration, as well as the possibility of co-usage with other agents.

Upon improvement of a subject's condition, a maintenance dose of a compound, composition or combination of this invention may be administered, if necessary. Subsequently, the dosage or frequency of administration, or both, may be reduced, as a function of the symptoms, to a level at which the improved condition is retained when the symptoms have been alleviated to the desired level, treatment should cease. The subject may, however, require intermittent treatment on a long-term basis upon any recurrence of disease symptoms.

It will be understood, however, that the total daily usage of the compounds and compositions of the present invention will be decided by the attending physician within the scope of sound medical judgment. The specific inhibitory dose for any particular patient will depend upon a variety of factors including the disorder being treated and the severity of the disorder; the activity of the specific compound employed; the specific composition employed; the age, body weight, general health, sex and diet of the patient; the time of administration, route of administration, and rate of excretion of the specific compound employed; the duration of the treatment; drugs used in combination or coincidental with the specific compound employed; and like factors well known in the medical arts.

In one aspect, the invention provides a method of selectively inhibiting the activity of each of HDAC1, HDAC2, and/or HDAC6 over other HDACs in a subject, comprising administering a compound of Formula I, Formula II, Formula III, or any of the compounds presented in Table 1, or pharmaceutically acceptable salts thereof.

In one embodiment, the compound has a selectivity for each of HDAC1, HDAC2 and HDAC6 of about 2 to 1000 fold greater than for other HDACs. In another embodiment, the compound has a selectivity for each of HDAC1, HDAC2, and or HDAC6 when tested in a HDAC enzyme assay of about 2 to 1000 fold greater than for other HDACs.

In another aspect, the invention provides a method of treating a disease mediated by an HDAC, specifically HDAC1, HDAC2, or HDAC6 in a subject comprising administering to the subject a compound of Formula I, Formula II, Formula III, or any of the compounds presented in Table 1, and pharmaceutically acceptable salts thereof.

In another aspect, the invention provides a method of treating a disease mediated by one or more HDACs in a subject comprising administering to the subject in need thereof a compound of Formula I, Formula II, Formula III, or any of the compounds presented in Table 1, or pharmaceutically acceptable salts thereof.

Inhibition of HDAC1 and HDAC2 is sufficient to derepress fetal globin. In cultured human CD34+ bone marrow cells undergoing erythroid differentiation, these compounds induced a dose dependent increase in fetal hemoglobin expression, with a 2-fold induction observed at 1 μM and 5-fold induction observed at 10 μM. Cytotoxicity of these compounds was minimal, showing IC₅₀ values ranging from 1 to 5 μM. The selective HDAC1 and HDAC2 inhibitors of the present invention have favorable pharmacokinetic profiles. Thus, the compounds are capable of derepressing fetal globin through HDAC inhibition. In a preferred embodiment, the compounds are able to treat sickle-cell disease or beta-thalessemia. Further, the compounds are able to treat a subject suffering from or susceptible to a hemoglobinopathy.

Inhibition of HDAC, including inhibition of HDAC1 and HDAC2 by selective compounds, can induce the expression of genes associated with synapse formation and memory in cultured neurons. In addition, inhibition of HDAC2 by gene disruption can lead to the formation of new synapses and increase cognitive performance in mice. Inhibition of HDAC6 by selective molecules can reverse the effects of neurodegenerative transgenes in mice, including amyloid precursor protein and presenelin 1. The selective inhibitors of HDAC1, HDAC2 and HDAC6 of the present invention would be capable of enhancing synapse formation and reversing the effects of amyloid protein, thus lessening the symptoms of neurodegenerative diseases such as Alzheimer's disease by two complimentary mechanisms.

In another aspect, the invention provides a method of activating latent HIV in a subject comprising administering to the subject a compound of Formula I, Formula II, Formula III, or any of the compounds presented in Table 1. The same compounds can be used treat HIV infections. In another embodiment, the compounds can be used in combination with one or more anti-retroviral agents for the treatment of HIV infections. In an embodiment, the HIV infection is HIV-1.

Anti-retroviral agents that can be used in combination with the HDAC inhibitors of the instant invention include nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, protease inhibitors, virus uptake/adsorption inhibitors, virus receptor antagonists, viral fusion inhibitors, viral integrase inhibitors, entry inhibitor, co-receptor antagonist, cyclin dependent kinase inhibitor, and transcription inhibitors or other anti-retroviral agents used in treatment of HIV infection. Preferred anti-retroviral agents include efavirenz, indinavir sulfate, and raltegravir potassium

As discussed above, the present invention provides compounds useful for the treatment of various diseases. In certain embodiments, the compounds of the present invention are useful as inhibitors of histone deacetylases (HDACs) and thus are useful as anti-cancer agents, and thus may be useful in the treatment of cancer, by effecting tumor cell death or inhibiting the growth of tumor cells. The compounds of the invention are capable of inducing apoptosis in cancer cells thereby able to treat a disease such as a cancer or proliferation disease.

In certain embodiments, the cancer is lung cancer, colon and rectal cancer, breast cancer, prostate cancer, liver cancer, pancreatic cancer, brain cancer, kidney cancer, ovarian cancer, stomach cancer, skin cancer, bone cancer, gastric cancer, breast cancer, glioma, gliobastoma, neuroblastom, hepatocellular carcinoma, papillary renal carcinoma, head and neck squamous cell carcinoma, leukemia, lymphomas, myelomas, retinoblastoma, cervical cancer, melanoma and/or skin cancer, bladder cancer, uterine cancer, testicular cancer, esophageal cancer, and solid tumors. In some embodiments, the cancer is lung cancer, colon cancer, breast cancer, neuroblastoma, leukemia, or lymphomas. In a further embodiment, the cancer is non-small cell lung cancer (NSCLC) or small cell lung cancer.

In further embodiments, the cancer is a hematologic cancer, such as a leukemia or a lymphoma. In a certain embodiment, the lymphoma is Hodgkins lymphoma or Non Hodgkin's lymphoma. In certain embodiments, the inventive compounds are effective anticancer agents, which are active against leukemia cells and thus are useful for the treatment of leukemias, e.g., myeloid, lymphocytic, myelocytic and lymphoblastic leukemias.

In another aspect, the present invention provides for a method of treating a subject suffering from or susceptible to Hodgkins lymphoma or Non Hodgkin's lymphoma comprising administering to a subject in need thereof a therapeutically effective amount of a compound of the instant invention to thereby treat the subject suffering from or susceptible to Hodgkins lymphoma or Non Hodgkin's lymphoma.

In various embodiments, the invention provides a method of treating cancer in a subject further comprising co-administering one or more of a chemotherapeutic agent, radiation agent, hormonal agent, biological agent or an anti-inflammatory agent to the subject. In some embodiments the chemotherapeutic agent is azacitidine, decitabine, clofarabine, erlotinib, bortezomib, carfilzomib, ixazomib, tamoxifen, trastuzumab, raloxifene, doxorubicin, lenalidomide, pomalidomide, fluorouracil/5-fu, pamidronate disodium, anastrozole, exemestane, cyclophosphamide, epirubicin, letrozole, toremifene, fulvestrant, fluoxymesterone, methotrexate, megastrol acetate, docetaxel, paclitaxel, testolactone, aziridine, vinblastine, capecitabine, goselerin acetate, zoledronic acid, taxol, vinblastine, or vincristine.

In another embodiment, the chemotherapeutic agent is an aromatase inhibitor.

In an embodiment, the biological agent is rituximab, ipilimumab, bevacizumab, cetuximab, panitumumab, trastuzumab, or other monoclonal antibodies used for the treatment of cancer.

Methods delineated herein include those wherein the subject is identified as in need of a particular stated treatment. Identifying a subject in need of such treatment can be in the judgment of a subject or a health care professional and can be subjective (e.g. opinion) or objective (e.g. measurable by a test or diagnostic method).

Also, as discussed above, the compounds of the invention are selective inhibitors of HDAC1, HDAC2, and/or HDAC6 and, as such, are useful in the treatment of disorders modulated by these histone deacetylases (HDACs). For example, compounds of the invention may be useful in the treatment of cancer (e.g., lung cancer, colon cancer, breast cancer, neuroblastoma, leukemia, or lymphomas, etc.). Accordingly, in yet another aspect, according to the methods of treatment of the present invention, tumor cells are killed, or their growth is inhibited by contacting said tumor cells with an inventive compound or composition, as described herein.

Thus, in another aspect of the invention, methods for the treatment of cancer are provided comprising administering a therapeutically effective amount of an inventive compound (i.e., of any of the formulae herein), as described herein, to a subject in need thereof. In certain embodiments, the subject is identified as in need of such treatment. In certain embodiments, a method for the treatment of cancer is provided comprising administering a therapeutically effective amount of an inventive compound, or a pharmaceutical composition comprising an inventive compound to a subject in need thereof, in such amounts and for such time as is necessary to achieve the desired result. In certain embodiments of the present invention a “therapeutically effective amount” of the inventive compound or pharmaceutical composition is that amount effective for killing or inhibiting the growth of tumor cells. The compounds and compositions, according to the method of the present invention, may be administered using any amount and any route of administration effective for killing or inhibiting the growth of tumor cells. Thus, the expression “amount effective to kill or inhibit the growth of tumor cells,” as used herein, refers to a sufficient amount of agent to kill or inhibit the growth of tumor cells. The exact amount required will vary from subject to subject, depending on the species, age, and general condition of the subject, the severity of the infection, the particular anticancer agent, its mode of administration, and the like.

In certain embodiments, the method involves the administration of a therapeutically effective amount of the compound or a pharmaceutically acceptable derivative thereof to a subject (including, but not limited to a human or animal) in need of it. In certain embodiments, the inventive compounds as useful for the treatment of cancer and other proliferative disorders including, but not limited to lung cancer (e.g. non-small cell lung cancer), colon and rectal cancer, breast cancer, prostate cancer, liver cancer, pancreatic cancer, brain cancer, kidney cancer, ovarian cancer, stomach cancer, skin cancer, bone cancer, gastric cancer, breast cancer, glioma, gliobastoma, neuroblastoma, hepatocellular carcinoma, papillary renal carcinoma, head and neck squamous cell carcinoma, leukemia (e.g., CML, AML, CLL, ALL), lymphomas (non-Hodgkin's and Hodgkin's), myelomas, retinoblastoma, cervical cancer, melanoma and/or skin cancer, bladder cancer, uterine cancer, testicular cancer, esophageal cancer, and solid tumors.

Provided in some embodiments are methods for inhibiting migration of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof. The HDAC1, HDAC2, and/or HDAC6 selective inhibitor can be any compound selected from the group consisting of a compound of Formula I, Formula II, Formula III, any of the compounds presented in Table 1, Compound X, and Compound Y.

Provided in some embodiments are methods for inducing maturation of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof. The HDAC1, HDAC2, and/or HDAC6 selective inhibitor can be any compound selected from the group consisting of a compound of Formula I, Formula II, Formula III, any of the compounds presented in Table 1, Compound X, and Compound Y.

Provided in some embodiments are methods for altering cell cycle progression of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof. The HDAC1, HDAC2, and/or HDAC6 selective inhibitor can be any compound selected from the group consisting of a compound of Formula I, Formula II, Formula III, any of the compounds presented in Table 1, Compound X, and Compound Y.

Provided in some embodiments are methods for decreasing viability and survival of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof. The HDAC1, HDAC2, and/or HDAC6 selective inhibitor can be any compound selected from the group consisting of a compound of Formula I, Formula II, Formula III, any of the compounds presented in Table 1, Compound X, and Compound Y.

Provided in some embodiments are methods for inducing differentiation of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof. The HDAC1, HDAC2, and/or HDAC6 selective inhibitor can be any compound selected from the group consisting of a compound of Formula I, Formula II, Formula III, any of the compounds presented in Table 1, Compound X, and Compound Y.

Provided in some embodiments are methods for enhancing low-concentration ATRA treatment of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof. The HDAC1, HDAC2, and/or HDAC6 selective inhibitor can be any compound selected from the group consisting of a compound of Formula I, Formula II, Formula III, any of the compounds presented in Table 1, Compound X, and Compound Y.

Provided in some embodiments are methods for inducing cell cycle arrest of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof. The HDAC1, HDAC2, and/or HDAC6 selective inhibitor can be any compound selected from the group consisting of a compound of Formula I, Formula II, Formula III, any of the compounds presented in Table 1, Compound X, and Compound Y.

Provided in some embodiments are methods for treating neuroblastoma in a subject comprising administering to the subject a therapeutically effective amount of Compound 001, Compound X, or Compound Y.

In certain embodiments, the invention provides a method of treatment of any of the disorders described herein, wherein the subject is a human.

In accordance with the foregoing, the present invention further provides a method for preventing or treating any of the diseases or disorders described above in a subject in need of such treatment, which method comprises administering to said subject a therapeutically effective amount of a compound of the invention or a pharmaceutically acceptable salt thereof. For any of the above uses, the required dosage will vary depending on the mode of administration, the particular condition to be treated and the effect desired.

EXAMPLES

Examples have been set forth below for the purpose of illustration and to describe certain specific embodiments of the invention. However, the scope of the claims is not to be in any way limited by the examples set forth herein. Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art and such changes and modifications including, without limitation, those relating to the chemical structures, subtitutents, derivatives, formulations and/or methods of the invention may be made without departing from the spirit of the invention and the scope of the appended claims. Definitions of the variables in the structures in the schemes herein are commensurate with those of corresponding positions in the formulae presented herein.

Example 1 Synthesis of 2-((1-acetyl-4-phenylpiperidin-4-yl)amino)-N-hydroxypyrimidine-5-carboxamide (Compound 003)

Step 1:

To a solution of 1 (10.4 g, 56.5 mmol) and TEA (11.4 g, 113 mmol) in DCM (60 mL) was added dropwise CbzCl (10 g, 56.5 mmol) over 30 mins at 0° C. Then the mixture was stirred at room temperature (r.t.) for 6 hrs. H₂O(50 ml) was added, the organic layer was washed with aqueous NaCl, dried by anhydrous Na₂SO₄, concentrated in vacuo and the residue was purified by silica gel chromatography (PE/EA=20:1) to afford compound 2 as a white solid (11.6 g, yield: 70%).

Step 2:

To a flask containing compound 3 (1.52 g, 13.1 mmol) and compound 2 (3 g, 10.9 mol) in DMF (25 ml) was added NaH (1.09 g, 27.2 mmol) at 0° C. It was stirred at 60° C. for 3 hrs. H₂O was added, the resulting mixture was extracted with ethyl acetate (EA). The combined EA layers were concentrated in vacuo and the residue was purified by silica gel chromatography (PE/EA=2:1) to afford compound 4 as a yellow solid (1.9 g, yield: 54%).

Step 3:

To a mixture of compound 4 (1.89 g, 5.91 mmol) in DMSO (15 mL) was added K₂CO₃ (2.4 g, 17.7 mmol), the mixture was stirred at 60° C. Then to the reaction 30% H₂O₂ (17 ml, 177 mmol) was added dropwise. After the reaction was complete, H₂O was added, and the reaction mixture was filtered. The resulting white solid was dried to afford compound 5 1.99 g, yield: 70%).

Step 4:

A mixture of compound 5 (6.2 g, 18.3 mmol), NaClO (11 ml, 25.6 mol), and 3N NaOH (17 mL, 51.3 mmol) in t-BuOH (40 mL) was stirred at 0° C. to r.t. overnight. The mixture was concentrated, extracted with EA (30 mL×2), washed with aqueous NaCl, dried by Na₂SO₄, and concentrated to afford compound 6 (4.5 g, yield: 80%).

Step 5:

To a solution of compound 6 (2.0 g, 6.45 mmol) in Dioxane (18 mL) was added ethyl 2-chloropyrimidine-5-carboxylate (1.08 g, 5.80 mmol), N,N-Diisopropylethylamine (DIPEA) (1.7 g, 12.9 mmol) at 105° C. The reaction was stirred overnight. The reaction mixture was concentrated in vacuo, and the residue was purified by silica gel chromatography (PE/EA=6:1) to give compound 7 (1.5 g, yield: 51%).

Step 6:

HBr/AcOH (6.0 mL) was added to a flask containing compound 7 (3.0 g, 6.52 mmol) at r.t. for 3 hrs. Then 12 ml Et₂O was added, the reaction mixture filtered, the solid was dried to give compound 8 (1.85 g, yield: 70%) as a yellow solid.

Step 7:

To a solution of compound 8 (100 mg, 0.31 mmol) in DCM (4 mL) was added Ac₂O (47 mg, 0.46 mmol), and Et₃N (0.5 ml) at r.t. The reaction was stirred for 2 hrs and the reaction mixture was concentrated in vacuo to give compound 9 (120 g, yield: 100%).

Step 8:

To a solution of compound 9 (20 mg, 0.33 mmol) in MeOH (2 mL) and DCM (1 ml) at 0° C. was added NH₂OH (0.4 ml) and stirred for 10 mins. Then NaOH/MeOH (0.8 ml) was added and the reaction was stirred for 2 hrs. The mixture was concentrated, adjusted to a pH=5 using 2N HCl, extracted with EA (10 ml) and purified by Pre-HPLC to afford 2-((1-acetyl-4-phenylpiperidin-4-yl)amino)-N-hydroxypyrimidine-5-carboxamide (18 mg, 16%). ¹H NMR (500 MHz, DMSO): δ 10.95 (s, 1H), 8.98 (s, 1H), 8.62 (s, 1H), 8.33 (s, 1H), 8.23 (s, 1H), 7.38 (d, J=7.6 Hz, 2H), 7.27 (t, J=7.7 Hz, 2H), 7.16 (t, J=7.3 Hz, 1H), 4.28 (d, J=13.2 Hz, 1H), 3.72 (d, J=13.6 Hz, 1H), 3.39-3.28 (m, 1H), 2.85 (t, J=12.3 Hz, 1H), 2.61 (t, J=12.5 Hz, 2H), 2.01 (s, 3H), 1.97-1.86 (m, 1H), 1.77 (t, J=11.0 Hz, 1H). LCMS: m/z=356 (M+H)⁺

Example 2 Synthesis of benzyl 4-((5-(hydroxycarbamoyl)pyrimidin-2-yl)amino)-4-phenylpiperidine-1-carboxylate (Compound 002)

To a solution of compound 7 (460 mg, 1.0 mmol) in MeOH (10 mL) and DCM (3 ml) at 0° C. was added NH₂OH (1.0 ml) and stirred for 10 mins. NaOH/MeOH (2.0 ml) was added and the reaction was stirred for 2 hrs. The mixture was concentrated, adjusted to pH=5 using 2N HCl, extracted with EA (10 ml), washed with aqueous NaCl, dried by Na₂SO₄, and concentrated to afford benzyl 4-((5-(hydroxycarbamoyl)pyrimidin-2-yl)amino)-4-phenylpiperidine-1-carboxylate (400 mg, 89%). ¹H NMR (500 MHz, DMSO) δ 10.94 (s, 1H), 8.97 (s, 1H), 8.61 (s, 1H), 8.34 (s, 1H), 8.21 (s, 1H), 7.40-7.35 (m, 6H), 7.32 (dt, J=9.1, 4.5 Hz, 1H), 7.26 (t, J=7.7 Hz, 2H), 7.15 (t, J=7.3 Hz, 1H), 5.08 (s, 2H), 3.92 (d, J=13.1 Hz, 2H), 3.15 (m, 2H), 2.60 (s, 2H), 1.87 (dd, J=12.8, 9.1 Hz, 2H). LCMS: m/z=448 (M+H)⁺

Example 3 Synthesis of N-hydroxy-2-((4-phenyl-1-(phenylcarbamoyl)piperidin-4-yl)amino)pyrimidine-5-carboxamide (Compound 001)

Step 1:

To a solution of compound 8 (85 mg, 0.26 mmol) in THF (4 mL) was added isocyanatobenzene (46 mg, 0.39 mmol), DIPEA (0.2 ml) at r.t. The reaction was stirred for 2 hrs. and subsequently concentrated in vacuo to give compound 9 (80 g, yield: 69%).

Step 2:

To a solution of compound 9 (80 mg, 0.18 mmol) in MeOH (3 mL) and DCM (1 ml) at 0° C. was added NH₂OH (0.2 ml). The reaction was stirred for 10 mins, at which time NaOH/MeOH (0.4 ml) was added. The reaction was stirred for 2 hrs. The resulting reaction mixture was concentrated, adjusted to PH=5 using 2N HCl, extracted with EA (10 ml), and purified by Pre-HPLC to afford N-hydroxy-2-((4-phenyl-1-(phenylcarbamoyl)piperidin-4-yl)amino)pyrimidine-5-carboxamide (14 mg, 17%). ¹H NMR (500 MHz, DMSO) δ 10.83 (s, 1H), 8.96 (s, 1H), 8.60 (s, 1H), 8.49 (s, 2H), 8.37 (s, 1H), 8.20 (s, 1H), 7.47-7.46 (d, J=7.6 Hz, 2H), 7.41-7.39 (d, J=7.4 Hz, 2H), 7.29-7.26 (t, J=7.7 Hz, 2H), 7.23-7.20 (m, J=7.7 Hz, 2H), 7.18-7.15 (t, J=7.3 Hz, 1H), 6.92 (t, J=7.3 Hz, 1H), 4.03 (d, J=13.2 Hz, 2H), 3.13 (t, J=12.1 Hz, 2H), 2.64 (d, J=13.0 Hz, 2H), 1.90 (t, J=11.0 Hz, 2H). LCMS: m/z=433 (M+H)⁺

Example 4 Synthesis of ethyl 4-((5-(hydroxycarbamoyl)pyrimidin-2-yl)amino)-4-phenylpiperidine-1-carboxylate (Compound 004)

Step 1:

To a solution of compound 8 (106 mg, 1.0 mmol), ethyl chloroformate (400 mg, 1.0 mmol) in 5 ml THF was added DIPEA (252 mg, 2.0 mmol). The mixture was stirred at r.t. for 4 hrs. LCMS monitored the reaction to completion. Upon completion, the reaction mixture was concentrated and the residue was purified by flash chromatography with PE/EA from 6:1 to 5:1 to give the target compound, compound 9 (320 mg, 82%).

Step 2:

To a solution of compound 9 (300 mg, 0.8 mmol) in 5 ml CH₃OH/CH₂Cl₂ was added NH₂OH (0.8 ml) dropwise at 0° C. The reaction was then stirred for 10 min. at 0° C. NaOH/CH₃OH was added into the solution slowly and the reaction continued stirring at 0° C. for 2 hrs. After the pH of the solution was adjusted to 6 by using conc. HCl, the target compound was precipitated from the solution as a white solid, washed by the mixing solvent of EA and PE to give ethyl 4-((5-(hydroxycarbamoyl)pyrimidin-2-yl)amino)-4-phenylpiperidine-1-carboxylate as a white solid (200 mg, 65%). ¹H NMR (500 MHz, DMSO) δ 10.93 (s, 1H), 8.95 (s, 1H), 8.60 (s, 1H), 8.34 (s, 1H), 8.17 (s, 1H), 7.38 (d, J=7.7 Hz, 2H), 7.26 (t, J=7.7 Hz, 2H), 7.15 (t, J=7.2 Hz, 1H), 4.07-4.00 (m, 2H), 3.88 (d, J=11.1 Hz, 2H), 3.11 (s, 2H), 2.60 (d, J=12.6 Hz, 2H), 1.86 (td, J=13.1, 4.3 Hz, 2H), 1.20-1.17 (m, 3 nH). LCMS: m/z=386 (M+H)⁺

Example 5 Synthesis of 2-((1-acetyl-4-isopropylpiperidin-4-yl)amino)-N-hydroxypyrimidine-5-carboxamide (Compound 005)

Step 1:

To a solution of compound 1 (3 g, 14.28 mmol) in a 3-neck-flask flushed with N₂ was added lithium bis(trimethylsilyl)amide (LiHDMS) (1M, 21.4 ml) at −78° C. The reaction was stirred for 3 h at which time 2-iodopropane (3.6 g, 21.43 mmol) was added slowly. The reaction solution was stirred at −78° C., and then warmed to r.t. overnight. The mixture was quenched with H₂O (2 ml), concentrated, dissolved in EA (200 ml), and washed with water (100 ml×2) and saturated NaCl(aq, 100 ml). The organic layer was concentrated to afford compound 2 as a brown solid (4 g, 100%).

Step 2:

To a solution of compound 2 (1 g, 3.97 mmol) in DMSO (30 ml) was added K₂CO₃ (1.6 g, 11.9 mmol) stirred at 60° C. Over a period of 2 hrs, H₂O₂ (30% aq., 5 ml) was added dropwise. TLC was used to monitor completion of the reaction. EA (100 ml) was added to the reaction mixture and subsequently washed with water (50 ml×2) and saturated NaCl(aq, 50 ml). The combined organic solutions were dried with anhydrous Na₂SO₄. The solvent was removed in vacuo to obtain compound 3 as a white solid (1 g, 90%).

Step 3:

To a solution of compound 3 (2.7 g, 10 mmol) in acetonitrile (AN) (50 ml) was added KOH (4N, aq., 50 ml) and 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) (2.81 g, 5 mmol) at 0° C. The reaction was stirred at r.t. overnight. The mixture was concentrated and 1N HCl was added to adjust the pH to ˜6. The resulting mixture was extracted with EA (50 ml). The aqueous phase was then adjusted to pH˜9 by addition of KOH, and was subsequently extracted with EA (50 ml×3). The EA phase was dried with anhydrous Na₂SO₄ and the solvent was concentrated to obtain compound 4 as a colorless liquid (1 g, 40%).

Step 4:

A solution of compound 4 (500 mg, 2.06 mmol) and ethyl 2-chloropyrimidine-5-carboxylate (384 mg, 2.06 mmol) in N-methyl-2-pyrrolidone (NMP) (10 ml) flushed with N₂ was stirred at 140° C. for 1 hour. EA (100 ml) was added to the reaction and resulting mixture was washed with water (50 ml×2) and saturated NaCl (aq, 50 ml). The resulting organic solution was concentrated and purified by silica gel chromatography column (PE/EA=5/1) to obtain compound 5 as a white solid (120 mg 15%).

Step 5:

To a solution of compound 5 (200 mg, 0.51 mmol) in DCM (5 ml) was added TFA (2 ml). The reaction was stirred at r.t. for 30 min. The mixture was concentrated to obtain compound 6 as a brown liquid (200 mg, 90%).

Step 6:

To a solution of compound 6 (200 mg, 0.709 mmol) in DCM was added Et₃N (214 mg, 2.13 mmol) and acetyl chloride (56 mg, 0.709 mmol) at 0° C. The reaction stirred for 1 hour at which time the reaction mixture was concentrated to obtain the compound 7 as a brown liquid (220 mg, 95%)

Step 7:

To a solution of 7 (220 mg) in MeOH (2 ml) was added NH₂OH (50% aq, 2 ml) and NaOH (saturated in MeOH 2 ml) at 0° C. The reaction stirred for 1 hour. The reaction mixture was then adjusted to a pH of ˜7 with 4N HCl(aq.), concentrated in vacuo, and purified by Pre-HPLC to obtain compound 8 as a white solid (68 mg, 35%). ¹H NMR (500 MHz, DMSO): δ 10.97 (s, 1H), 8.57 (s, 2H), 7.44 (s, 1H), 4.28-4.20 (m, 1H), 3.69-3.58 (m, 1H), 3.21-3.06 (m, 1H), 2.66-2.57 (m, 1H), 2.57-2.53 (m, 1H), 2.42-2.24 (m, 2H), 1.97 (s, 3H), 1.57-1.45 (m, 1H), 1.41-1.28 (m, 1H), 0.82 (d, J=6.9 Hz, 6H). LCMS: m/z=322 (M+H)⁺

Example 6 Synthesis of ethyl 4-((5-(hydroxycarbamoyl)pyrimidin-2-yl)amino)-4-isopropylpiperidine-1-carboxylate (Compound 006)

Step 1:

To a solution of compound 6 (200 mg, 0.709 mmol) in DCM was added Et₃N (214 mg, 2.13 mmol) and ethyl carbonochloridate (77 mg, 0.709 mmol) at 0° C. for 1 hour. The reaction mixture was concentrated to obtain compound 9 as a brown liquid (250 mg, 95%).

Step 2:

To a solution of compound 9 (250 mg) in MeOH (2 ml) was added NH₂OH (50% aq., 2 ml) and NaOH (saturated in MeOH, 2 ml) at 0° C. The mixture was stirred for 1 hour after which the reaction solution was adjusted to a pH of ˜7 with 4N HCl(aq.), concentrated, and purified by Pre-HPLC to obtain ethyl 4-((5-(hydroxycarbamoyl)pyrimidin-2-yl)amino)-4-isopropylpiperidine-1-carboxylate as a white solid (67 mg, 30%). ¹H NMR (500 MHz, DMSO): δ 10.95 (m, 1H), 8.97 (m, 1H), 8.57 (s, 2H), 7.40 (s, 1H), 4.01 (d, J=7.1 Hz, 2H), 3.89-3.73 (m, 2H), 3.53-3.23 (m, 2H), 3.02-2.78 (m, 2H), 2.60-2.52 (m, 1H), 2.40-2.26 (m, 2H), 1.44 (d, J=4.4 Hz, 2H), 1.16 (t, J=7.1 Hz, 3H), 0.82 (d, J=6.9 Hz, 6H). LCMS: m/z=352 (M+H)⁺

Example 7 Synthesis of benzyl 4-((5-(hydroxycarbamoyl)pyrimidin-2-yl)amino)-4-isopropylpiperidine-1-carboxylate (Compound 007)

Step 1:

To a solution of compound 6 (200 mg, 0.709 mmol) in DCM was added Et₃N (214 mg, 2.13 mmol) and benzyl carbonochloridate (181 mg, 1.06 mmol) at 0° C. for 2 hrs. The mixture was concentrated to obtain compound 11 as a brown liquid (300 mg, 95%).

Step 2:

To a solution of compound 11 (300 mg) in MeOH (2 ml) was added NH₂OH (50% aq, 2 ml) and NaOH (saturated in MeOH, 2 ml) at 0° C. The mixture stirred for 1 hour after which the reaction solution was adjusted to a pH of −7 with 4N HCl(aq.), concentrated, and purified by Pre-HPLC to obtain benzyl 4-((5-(hydroxycarbamoyl)pyrimidin-2-yl)amino)-4-isopropylpiperidine-1-carboxylate as a white solid (78.1 mg, 28%). ¹H NMR (500 MHz, DMSO) δ 10.99 (m, 1H), 8.57 (m, 2H), 7.53-7.26 (m, 6H), 5.06 (s, 2H), 3.94-3.72 (m, 2H), 3.07-2.77 (m, 2H), 2.61-2.53 (m, 1H), 2.42-2.24 (m, 2H), 1.59-1.29 (m, 2H), 0.81 (d, J=6.8 Hz, 6H). LCMS: m/z=414 (M+H)⁺.

Example 8 Synthesis of N-hydroxy-2-((1-((4-methoxyphenyl)carbamoyl)-4-phenylpiperidin-4-yl)amino)pyrimidine-5-carboxamide (Compound 008)

Step 1:

To a solution of compound 1 (10 g, 56.5 mmol) in DCM (50 mL) was added TEA (11.4 g, 113 mmol), followed by CbzCl (10.4 g, 56.5 mmol) while the system was in a water bath. The mixture was stirred for 3 hrs at r.t. Water (50 ml) was added to the reaction mixture and extracted with EA (150 ml×2). The organic phase was washed with saturated salt and dried over Na₂SO₄. Concentration and purification by silica gel column with EA/PE=1/20 yielded compound 2 (3 g, 18%) as an oil.

Step 2:

To a solution of compound 2 (100 g, 0.36 mol) and benzyl cyanide (59 g, 0.43 mol) in DMF (400 ml) was added NaH (37 g, 0.94 mol) at 0° C. After increasing the temperature to 60° C., the mixture was stirred at 60° C. overnight. TLC was used to monitor the reaction to completion. After cooling, water was added into the mixture resulting in a green solid. The target compound was purified by flash chromatography with PE/EA from 30:1 to 2:1 to yield compound 3 (38 g, 79%) as a white solid.

Step 3:

To a solution of compound 3 (38 g, 112 mmol) in 300 ml DMSO was added 30% H₂O₂ (190 ml, 2248 mmol) slowly at 0° C. followed by stirring for 30 mins. Then the temperature was slowly increased to 40° C. and stirred for an additional 30 mins. After increasing the temperature to 60° C., the mixture was stirred at 60° C. overnight. TLC was used to monitor the reaction to completion. After cooling, water was added into the mixture to give a white solid, which was isolated by filtration (38 g, ˜95%).

Step 4:

To a solution of compound 4 (38 g, 106 mmol) in 400 ml BuOH was slowly added NaClO (64.2 ml, 149 mmol) followed by 3N NaOH (99 ml, 298 mmol) at 0° C. Then the mixture was stirred at r.t. overnight. TLC was used to monitor the reaction to completion. The mixture was concentrated and extracted with EtOAc. The organic layer was separated, washed and dried. Then the mixture was dissolved in Et₂O, and the pH was adjusted to 2 using HCl/Dioxane. The precipitate was collected, yielding the target compound 5 (38 g 100%).

Step 5:

To a solution of compound 5 (9.6 g, 26 mmol), 2-Cl-pyrimidine (4.9 g, 26 mmol) in 150 ml 1,4-Dioxane was added DIPEA (7.7 g, 60 mmol). The mixture was stirred at 110° C. overnight. LCMS was used to monitor the reaction to completion. Water (50 ml) was added and the mixture was extracted with EtOAc. The combined organic extracts were washed and dried. The target compound 6 (11 g, 90%) was purified by flash chromatography with PE/EA from 30:1 to 2:1.

Step 6:

To a solution of compound 6 (1 g, 2.17 mmol) in MeOH (15 mL) was added Pd/C (0.1 g, 10% wq) under N₂. The reaction was stirred under an H₂ atmosphere overnight, after which it was filtered through celite and washed with MeOH. Concentration yielded compound 7 (690 mg, 98%) as a light yellow solid.

Step 7:

To a mixture of compound 7 (81 mg, 0.2 mmol) and 1-isocyanato-4-methoxybenzene (21 mg, 0.2 mmol) in THF (4 ml) was added DIPEA (46 mg, 0.36 mmol). The reaction was stirred for 1 h. at r.t., concentrated, and purified by gel chromatography (DCM:MeOH=10:1) to afford 8 (80 mg, 84%) as a white solid.

Step 8:

To a solution of compound 8 (80 mg, 0.16 mmol) in MeOH (3 mL) and DCM (1 ml) at 0° C. was added NH₂OH (0.2 ml) followed by stirring for 10 min. Then NaOH/MeOH (0.4 ml) was added and the reaction was stirred for 2 h. The reaction was concentrated and the pH was adjusted to 5, after which it was extracted with EA (10 ml). Purification by Pre-HPLC afforded the desired product, Compound 008 (15 mg, 21%). ¹H NMR (500 MHz, DMSO) δ 8.60 (s, 1H), 8.32 (s, 2H), 8.19 (s, 1H), 7.40 (d, J=7.5 Hz, 2H), 7.34 (d, J=9.0 Hz, 2H), 7.27 (t, J=7.7 Hz, 2H), 7.16 (t, J=7.3 Hz, 1H), 6.81 (d, J=9.0 Hz, 2H), 4.00 (d, J=13.4 Hz, 2H), 3.70 (s, 3H), 3.11 (t, J=12.2 Hz, 2H), 2.63 (d, J=12.3 Hz, 2H), 1.89 (t, J=11.1 Hz, 2H). LCMS: m/z=463 (M+H)⁺.

Example 9 Synthesis of 2-((1,4-diphenylpiperidin-4-yl)amino)-N-hydroxypyrimidine-5-carboxamide (Compound 009)

Step 1:

A mixture of compound 1 (200 mg, 0.49 mmol), bromobenzene (77 mg, 0.49 mmol), Pd₂(dba)₃ (20 mg, 0.02 mmol), Xantphos (12 mg, 0.02 mmol) and Cs₂CO₃ (480 mg, 1.47 mmol) in toluene (8 ml) was stirred at 95° C. overnight under N₂. After completion, the reaction was filtered and concentrated, and purified by gel chromatography (PE: EA=1:1) to afford compound 2 (60 mg, 20%) as a white solid.

Step 2:

To a solution of compound 2 (60 mg, 0.15 mmol) in MeOH (3 ml) and DCM (1 ml) at 0° C. was added NH₂OH (0.1 ml) followed by stirring for 10 mins. NaOH/MeOH (0.2 ml) was then added and stirred for 2 hrs. The reaction mixture was concentrated, adjusted to a pH of 5, and extracted with EA (10 ml). Purification by Prep-HPLC afforded the desired product, Compound 009 (18 mg, 32%). ¹HNMR (500 MHz, DMSO) δ 10.77 (s, 1H), 8.96 (s, 1H), 8.47 (d, J=118.1 Hz, 2H), 8.14 (s, 1H), 7.43 (d, J=7.5 Hz, 2H), 7.28 (t, J=7.7 Hz, 2H), 7.22-7.14 (m, 3H), 6.96 (d, J=8.1 Hz, 2H), 6.74 (t, J=7.2 Hz, 1H), 3.58 (d, J=12.2 Hz, 2H), 2.98 (t, J=11.6 Hz, 2H), 2.72 (d, J=12.4 Hz, 2H), 2.09 (dd, J=12.4, 9.3 Hz, 2H). LCMS: m/z=390 (M+H)⁺.

Example 10 Synthesis of 2-((1-((2-fluorophenyl)carbamoyl)-4-phenylpiperidin-4-yl)amino)-N-hydroxypyrimidine-5-carboxamide (Compound 010)

Step 1:

To a mixture of compound 1 (50 mg, 0.15 mmol) and 1-fluoro-2-isocyanatobenzene (21 mg, 0.15 mmol) in THF(4 ml) was added DIPEA(39 mg, 0.30 mmol) at r.t. followed by stirring for 1 hour. The reaction mixture was concentrated and purified by gel chromatography (PE:EA=1:1) to afford compound 2 (60 mg, 86%) as a white solid.

Step 2:

A procedure analogous to step 2 in Example 9 yielded Compound 010 (12 mg, 44%). ¹H NMR (500 MHz, DMSO) δ 10.84 (s, 1H), 8.94 (s, 1H), 8.32 (d, J=59.2 Hz, 3H), 8.18 (s, 1H), 7.47-7.35 (m, 3H), 7.28 (t, J=7.7 Hz, 2H), 7.17 (dd, J=13.9, 6.5 Hz, 2H), 7.10 (dd, J=6.7, 2.9 Hz, 2H), 3.98 (d, J=13.0 Hz, 2H), 3.15 (t, J=12.3 Hz, 2H), 2.64 (d, J=12.4 Hz, 2H), 1.92 (t, J=10.9 Hz, 2H). LCMS: m/z=451 (M+H)⁺.

Example 11 Synthesis of 2-((1-((3,4-dichlorophenyl)carbamoyl)-4-phenylpiperidin-4-yl)amino)-N-hydroxypyrimidine-5-carboxamide (Compound 011)

Step 1:

To a mixture of compound 1 (60 mg, 0.18 mmol) and 1,2-dichloro-4-isocyanatobenzene (34 mg, 0.18 mmol) in THF (4 ml) was added DIPEA (46 mg, 0.36 mmol) at r.t. followed by stirring for 1 hour. The reaction mixture was concentrated and purified by gel chromatography (PE:EA=1:1) to afford compound 2 (60 mg, 70%) as a white solid.

Step 2:

A procedure analogous to step 2 in Example 9 yielded Compound 011 (39 mg, 65%). ¹H NMR (500 MHz, DMSO) δ 10.93 (s, 1H), 8.98 (s, 1H), 8.78 (s, 1H), 8.62 (s, 1H), 8.35 (s, 1H), 8.24 (s, 1H), 7.87 (s, 1H), 7.47 (s, 2H), 7.40 (d, J=7.6 Hz, 2H), 7.27 (t, J=7.7 Hz, 2H), 7.21-7.12 (m, 1H), 4.02 (d, J=12.9 Hz, 2H), 3.15 (t, J=12.4 Hz, 2H), 2.65 (d, J=12.5 Hz, 2H), 1.91 (t, J=10.8 Hz, 2H). LCMS: m/z=502 (M+H)⁺.

Example 12 Synthesis of N-hydroxy-2-((1-(methyl(phenyl)carbamoyl)-4-phenylpiperidin-4-yl)amino)pyrimidine-5-carboxamide (Compound 012)

Step 1:

To a mixture of compound 1 (40 mg, 0.12 mmol) and methyl(phenyl)carbamic chloride (21 mg, 0.12 mmol) in THF (4 ml) was added DIPEA (31 mg, 0.24 mmol) at r.t. The reaction was stirred for 1 hr., concentrated, and purified by gel chromatography (PE:EA=1:1) to afford compound 2 (50 mg, 91%) as a white solid.

Step 2:

A procedure analogous to step 2 in Example 9 yielded Compound 012 (21 mg, 47%). ¹H NMR (500 MHz, DMSO) δ 8.57 (s, 1H), 8.28 (s, 1H), 8.08 (s, 1H), 7.35 (t, J=7.9 Hz, 2H), 7.29 (d, J=7.5 Hz, 2H), 7.24 (t, J=7.7 Hz, 2H), 7.14 (d, J=7.6 Hz, 3H), 7.08 (d, J=7.4 Hz, 1H), 3.61 (d, J=13.4 Hz, 2H), 3.09 (s, 3H), 2.90 (t, J=12.3 Hz, 2H), 2.44 (d, J=12.7 Hz, 2H), 1.69 (t, J=10.9 Hz, 2H). LCMS: m/z=447 (M+H)⁺.

Example 13 Synthesis of 2-((1-((3-fluorophenyl)carbamoyl)-4-phenylpiperidin-4-yl)amino)-N-hydroxypyrimidine-5-carboxamide (Compound 013)

Step 1:

A mixture of compound 1 (60 mg, 0.18 mmol) and 1-fluoro-3-isocyanatobenzene (25 mg, 0.18 mmol) in THF (4 ml) was added DIPEA (46 mg, 0.36 mmol) at r.t. The reaction as stirred for 1 hr, concentrated, and purified by gel chromatography (PE:EA=1:1) to afford compound 2 (60 mg, 71%) as a white solid.

Step 2:

A procedure analogous to step 2 in Example 9 yielded Compound 013 (40 mg, 68%). ¹H NMR (500 MHz, DMSO) δ 10.91 (s, 1H), 9.01 (s, 1H), 8.70 (s, 1H), 8.63 (s, 1H), 8.36 (s, 1H), 8.24 (s, 1H), 7.46 (d, J=12.3 Hz, 1H), 7.40 (d, J=7.6 Hz, 2H), 7.25 (dt, J=20.3, 7.8 Hz, 4H), 7.16 (t, J=7.3 Hz, 1H), 6.72 (t, J=7.6 Hz, 1H), 4.03 (d, J=13.4 Hz, 2H), 3.14 (t, J=12.2 Hz, 2H), 2.65 (d, J=12.7 Hz, 2H), 1.91 (t, J=10.9 Hz, 2H). LCMS: m/z=451 (M+H)⁺.

Example 14 Synthesis of 2-((1-((4-fluorophenyl)carbamoyl)-4-phenylpiperidin-4-yl)amino)-N-hydroxypyrimidine-5-carboxamide (Compound 014)

Step 1:

To a mixture of compound 1 (70 mg, 0.18 mmol) and 1-fluoro-4-isocyanatobenzene (25 mg, 0.18 mmol) in THF (4 ml) was added DIPEA (46 mg, 0.36 mmol) at r.t. The reaction was stirred for 1 hr, concentrated, and purified by gel chromatography (DCM:MeOH=10:1) to afford compound 2 (720 mg, 85%) as a white solid.

Step 2:

A procedure analogous to step 2 in Example 9 yielded Compound 014 (25 mg, 37%). ¹H NMR (500 MHz, DMSO) δ 10.76 (s, 1H), 8.94 (s, 1H), 8.70-8.07 (m, 4H), 7.51-7.43 (m, 2H), 7.40 (d, J=7.5 Hz, 2H), 7.27 (t, J=7.7 Hz, 2H), 7.16 (t, J=7.3 Hz, 1H), 7.06 (t, J=8.9 Hz, 2H), 4.02 (d, J=13.2 Hz, 2H), 3.13 (t, J=12.3 Hz, 2H), 2.64 (d, J=12.8 Hz, 2H), 1.90 (dd, J=12.6, 9.3 Hz, 2H). LCMS: m/z=451 (M+H)⁺.

Example 15 Synthesis of N-hydroxy-2-((4-phenyl-1-(p-tolylcarbamoyl)piperidin-4-yl)amino)pyrimidine-5-carboxamide (Compound 015)

Step 1:

A mixture of 1 (60 mg, 0.18 mmol) and 1-isocyanato-4-methylbenzene (25 mg, 0.18 mmol) in THF (4 ml) was added DIPEA (46 mg, 0.36 mmol) at r.t stirred for 1 hour, concentrated, purified by gel chromatography (DCM:MeOH=10:1) to afford 2 (70 mg, 85%) as white solid.

Step 2:

A procedure analogous to step 2 in Example 9 yielded Compound 015 (19 mg, 29%). ¹H NMR (500 MHz, DMSO) δ 8.38 (dd, J=107.5, 101.2 Hz, 4H), 7.31 (dd, J=48.2, 18.7 Hz, 6H), 7.16 (s, 1H), 7.01 (s, 2H), 4.00 (s, 2H), 3.11 (s, 2H), 2.62 (s, 2H), 2.21 (d, J=7.4 Hz, 3H), 1.89 (s, 2H). LCMS: m/z=447 (M+H)⁺.

Example 16 Synthesis of N-hydroxy-2-((1-(methylcarbamoyl)-4-phenylpiperidin-4-yl)amino)pyrimidine-5-carboxamide (Compound 016)

Step 1:

To a mixture of compound 1 (81 mg, 0.2 mmol) and methylcarbamic chloride (19 mg, 0.2 mmol) in THF (4 ml) was added DIPEA (46 mg, 0.36 mmol) at r.t. followed by stirring for 1 hr. The reaction was concentrated and purified by gel chromatography (DCM:MeOH=10:1) to afford compound 2 (50 mg, 61%) as a white solid.

Step 2:

A procedure analogous to step 2 in Example 9 yielded Compound 016 (22 mg, 46%). 1H NMR (500 MHz, DMSO) δ 10.71 (s, 1H), 8.95 (s, 1H), 8.59 (s, 1H), 8.34 (s, 1H), 8.12 (s, 1H), 7.37 (d, J=7.6 Hz, 2H), 7.26 (t, J=7.7 Hz, 2H), 7.15 (t, J=7.3 Hz, 1H), 6.40 (d, J=4.4 Hz, 1H), 3.80 (d, J=13.1 Hz, 2H), 2.98 (t, J=12.2 Hz, 2H), 2.60-2.53 (m, 5H), 1.80 (dd, J=12.6, 9.1 Hz, 2H). LCMS: m/z=371 (M+H)⁺.

Example 17 Synthesis of N-hydroxy-2-((4-phenyl-1-(phenylcarbamothioyl)piperidin-4-yl)amino)pyrimidine-5-carboxamide (Compound 017)

Step 1:

A procedure analogous to step 2 in Example 9 afforded compound 2 (40 mg, 58%).

Step 2:

To a mixture of compound 2 (40 mg, 0.13 mmol) and isothiocyanatobenzene (17 mg, 0.13 mmol) in THF (2 ml) was added DIPEA (34 mg, 0.26 mmol) at r.t. followed by stirring for 20 mins. The reaction mixture was concentrated and purified by Pre-HPLC to afford Compound 017 (13 mg, 22%) as a white solid. ¹H NMR (500 MHz, DMSO) δ 9.29 (s, 1H), 8.68-8.23 (m, 3H), 7.41 (d, J=7.6 Hz, 2H), 7.29 (t, J=5.1 Hz, 6H), 7.18 (t, J=7.2 Hz, 1H), 7.11-7.02 (m, 1H), 4.64 (d, J=11.3 Hz, 2H), 3.39 (d, J=12.0 Hz, 2H), 2.69 (d, J=13.0 Hz, 2H), 2.01 (t, J=11.2 Hz, 2H). LCMS: m/z=449 (M+H)⁺.

Example 18 Synthesis of 2-((1-((3-fluorophenyl)sulfonyl)-4-phenylpiperidin-4-yl)amino)-N-hydroxypyrimidine-5-carboxamide (Compound 018)

Step 1:

To a solution of compound 1 (55 mg, 0.14 mmol), 3-fluorobenzene sulfochloride (27 mg, 0.14 mmol) in 5 ml THF was added DIPEA (44 mg, 0.34 mmol). The mixture was stirred at r.t. for 2 h. LCMS was used to monitor the reaction to completion. The target compound (30 mg, 46%) was purified by flash chromatography with PE/EA (3:1).

Step 2:

To a solution of compound 2 (30 mg, 0.06 mmol) in 5 ml CH₃OH/CH₂Cl₂ was slowly added NH₂OH (2 ml) at 0° C. followed by stirring for 10 mins. Then NaOH/CH₃OH was slowly added to the solution and stirred for 3 h. After removing the solvent from the solution, the pH was adjusted to 6 by 2N HCl. The target compound, Compound 018, (13 mg, 46%) was purified by pre-HPLC. ¹H NMR (500 MHz, DMSO) δ 8.91 (s, 1H), 8.47 (s, 1H), 8.29 (s, 1H), 7.75-7.68 (m, 1H), 7.66-7.55 (m, 3H), 7.32 (d, J=7.7 Hz, 2H), 7.25 (t, J=7.7 Hz, 2H), 7.15 (t, J=7.3 Hz, 1H), 3.61 (d, J=11.3 Hz, 2H), 2.63 (t, J=12.2 Hz, 4H), 2.00 (s, 2H). LCMS: m/z=472 (M+H)⁺.

Example 19 Synthesis of 2-((1-((4-chlorophenyl)sulfonyl)-4-phenylpiperidin-4-yl)amino)-N-hydroxypyrimidine-5-carboxamide (Compound 019)

Step 1:

To a solution of compound 1 (70 mg, 0.17 mmol) and 4-chlorobenzene sulfochloride (36 mg, 0.17 mmol) in 5 ml THF was added DIPEA (44 mg, 0.34 mmol). The mixture was stirred at r.t. for 2 h. LCMS was used to monitor the reaction to completion. The target, compound 2, (56 mg, 65%) was purified by flash chromatography with PE/EA (3:1).

Step 2:

A procedure analogous to step 2 in Example 18 yielded Compound 019. ¹H NMR (500 MHz, DMSO) δ 8.40 (t, J=60.5 Hz, 2H), 8.02 (s, 1H), 7.79 (d, J=8.5 Hz, 2H), 7.73 (d, J=8.5 Hz, 2H), 7.32 (d, J=7.6 Hz, 2H), 7.24 (d, J=7.7 Hz, 2H), 7.15 (t, J=7.1 Hz, 1H), 3.59 (d, J=11.3 Hz, 2H), 2.62 (dd, J=25.8, 13.9 Hz, 4H), 1.99 (s, 2H). LCMS: m/z=488 (M+H)±.

Example 20 Synthesis of N-hydroxy-2-((4-phenyl-1-(o-tolylsulfonyl)piperidin-4-yl)amino)pyrimidine-5-carboxamide (Compound 020)

Step 1:

To a solution of compound 1 (55 mg, 0.14 mmol) and 2-methylbenzene sulfochloride (26 mg, 0.14 mmol) in 5 ml THF was added DIPEA (44 mg, 0.34 mmol). The mixture was stirred at r.t. for 2 h. LCMS was used to monitor the reaction to completion. The target compound (40 mg, 62.5%) was purified by flash chromatography with PE/EA (3:1).

Step 2:

A procedure analogous to step 2 in Example 18 yielded Compound 020. ¹H NMR (500 MHz, DMSO) δ 8.96 (s, 1H), 8.47 (s, 1H), 8.31 (s, 1H), 8.08 (s, 1H), 7.82 (d, J=8.1 Hz, 1H), 7.58 (t, J=7.0 Hz, 1H), 7.44 (dd, J=20.0, 7.7 Hz, 2H), 7.34 (d, J=7.6 Hz, 2H), 7.26 (t, J=7.7 Hz, 2H), 7.15 (t, J=7.2 Hz, 1H), 3.53 (d, J=12.1 Hz, 2H), 2.89 (t, J=12.0 Hz, 2H), 2.67 (s, 2H), 2.59 (s, 3H), 1.96 (s, 2H). LCMS: m/z=468 (M+H)⁺.

Example 21 Synthesis of N-hydroxy-2-((4-phenyl-1-tosylpiperidin-4-yl)amino)pyrimidine-5-carboxamide (Compound 021)

Step 1:

To a solution of compound 1 (55 mg, 0.14 mmol) and 4-methylbenzene sulfochloride (26 mg, 0.14 mmol) in 5 ml THF was added DIPEA (44 mg, 0.34 mmol). The mixture was stirred at r.t for 2 h. LCMS was used to monitor the reaction to completion. The target compound (48 mg, 75%) was purified by flash chromatography with PE/EA (3:1).

Step 2:

A procedure analogous to step 2 in Example 18 yielded Compound 021. ¹H NMR (500 MHz, DMSO) δ 10.85 (s, 1H), 8.97 (s, 1H), 8.51 (s, 1H), 8.28 (s, 1H), 7.65 (d, J=8.1 Hz, 2H), 7.45 (d, J=8.1 Hz, 2H), 7.32 (d, J=7.7 Hz, 2H), 7.24 (t, J=7.6 Hz, 2H), 7.14 (t, J=7.1 Hz, 1H), 3.56 (d, J=11.7 Hz, 2H), 2.66 (s, 2H), 2.56 (t, J=11.9 Hz, 2H), 2.41 (s, 3H), 2.00 (d, J=10.5 Hz, 2H). LCMS: m/z=468 (M+H)⁺.

Example 22 Synthesis of N-hydroxy-2-((4-phenyl-1-((4-(trifluoromethyl)phenyl)sulfonyl)piperidin-4-yl)amino)pyrimidine-5-carboxamide (Compound 022)

Step 1:

To a mixture of compound 1 (55 mg, 0.13 mmol) and 4-(trifluoromethyl)benzene-1-sulfonyl chloride (33 mg, 0.13 mmol) in THF (4 ml) was added DIPEA (31 mg, 0.24 mmol) at r.t. followed by stirring for 20 min. The reaction mixture was concentrated and purified by gel chromatography (PE:EA=2:1) to afford compound 2 (55 mg, 79%) as a yellow solid.

Step 2:

To a solution of compound 2 (60 mg, 0.1 mmol) in MeOH (3 mL) and DCM (1 ml) at 0° C. was added NH₂OH (0.1 ml) followed by stirring for 10 min. Then NaOH/MeOH (0.2 ml) was added and the reaction stirred for 2 hrs after which it was concentrated. The pH was adjusted to 5 and extracted with EA (10 ml). Purification by Pre-HPLC afforded Compound 022 (20 mg, 38%). ¹H NMR (500 MHz, DMSO) δ 10.94 (s, 1H), 8.57 (t, J=163.9 Hz, 3H), 8.03 (q, J=8.4 Hz, 5H), 7.30 (d, J=7.7 Hz, 2H), 7.24 (t, J=7.7 Hz, 2H), 7.15 (t, J=7.2 Hz, 1H), 3.64 (d, J=12.1 Hz, 2H), 2.65 (t, J=11.3 Hz, 4H), 2.01 (d, J=11.1 Hz, 2H). LCMS: m/z=522 (M+H)+.

Example 23 Synthesis of N-hydroxy-2-((4-phenyl-1-(phenylsulfonyl)piperidin-4-yl)amino)pyrimidine-5-carboxamide (Compound 023)

Step 1:

To a solution of compound 1 (80 mg, 0.25 mmol) and benzene sulfochloride (44 mg, 0.25 mmol) in 5 ml THF was added DIPEA (80 mg, 0.63 mmol). The mixture was stirred at r.t. for 3 h. LCMS was used to monitor the reaction to completion. The target compound (60 mg, 51%) was purified by flash chromagraphy with PE/EA (2:1).

Step 2:

A procedure analogous to step 2 in Example 18 yielded Compound 023. ¹H NMR (400 MHz, DMSO) δ 10.88 (s, 1H), 8.96 (s, 1H), 8.50 (s, 1H), 8.28 (s, 1H), 8.01 (s, 1H), 7.82-7.75 (m, 2H), 7.73 (t, J=7.3 Hz, 1H), 7.65 (t, J=7.4 Hz, 2H), 7.32 (d, J=7.6 Hz, 2H), 7.24 (t, J=7.7 Hz, 2H), 7.14 (t, J=7.2 Hz, 1H), 3.59 (d, J=11.7 Hz, 2H), 2.67 (d, J=12.8 Hz, 2H), 2.58 (t, J=11.9 Hz, 2H), 1.99 (t, J=11.1 Hz, 2H). LCMS: m/z=454 (M+H)⁺.

Example 24 Synthesis of 2-((1-((2,6-difluorophenyl)carbamoyl)-4-phenylpiperidin-4-yl)amino)-N-hydroxypyrimidine-5-carboxamide (Compound 024)

Step 1:

To a mixture of compound 1 (60 mg, 0.18 mmol) and 1,3-difluoro-2-isocyanatobenzene (28 mg, 0.18 mmol) in THF (4 ml) was added DIPEA (46 mg, 0.36 mmol) at r.t. followed by stirring for 20 mins. The reaction was concentrated and purified by gel chromatography (PE:EA=2:1) to afford compound 2 (70 mg, 81%) as a yellow solid.

Step 2:

A procedure analogous to step 2 in Example 9 yielded Compound 024 (28 mg, 43%). ¹H NMR (500 MHz, DMSO) δ 10.94 (s, 1H), 8.97 (s, 1H), 8.62 (s, 1H), 8.35 (s, 1H), 8.24 (d, J=12.1 Hz, 2H), 7.40 (d, J=7.5 Hz, 2H), 7.32-7.22 (m, 3H), 7.17 (t, J=7.3 Hz, 1H), 7.10 (t, J=8.0 Hz, 2H), 3.97 (d, J=13.5 Hz, 2H), 3.16 (t, J=12.4 Hz, 2H), 2.64 (d, J=12.6 Hz, 2H), 1.92 (t, J=10.9 Hz, 2H). LCMS: m/z=469 (M+H)⁺.

Examples 25-26 Synthesis of (R) and (S)N-hydroxy-2-((1-(3-methyl-2-phenylbutanoyl)-4-phenylpiperidin-4-yl)amino)pyrimidine-5-carboxamide (Compounds 025 and 026)

Step 1:

To a solution of compound 7 (200 mg, 0.50 mmol) and 3-methyl-2-phenylbutanoic acid (90 mg, 0.50 mmol) in 5 ml DMF was added HOAT (68 mg, 0.50 mmol), EDCI (78 mg, 050 mmol) and DIPEA (129 mg, 1 mmol). The mixture was stirred at 60° C. overnight and LCMS was used to monitor the reaction to completion. The racemic compound 8 (200 mg, 83%) was purified by filtration through silica gel after extraction by EA. Chiral-HPLC afforded R and S targets separately.

Step 2:

To a solution of each of the compounds from the above step (40 mg, 0.08 mmol) in 5 ml CH₃OH/CH₂Cl₂ was added NH₂OH (0.1 ml) slowly at 0° C. followed by stirring for 10 min. NaOH/CH3OH (0.3 ml) was added into the solution slowly and stirred for 2 h. After removing the solvent from the solution, the pH was adjusted to 6 by 2N HCl. The target compound was purified by pre-HPLC to afford Compound 025 (R) (26 mg, 26%). ¹H NMR (500 MHz, DMSO) δ 10.93 (s, 1H), 8.60 (s, 1H), 8.31 (s, 1H), 8.18 (d, J=6.4 Hz, 1H), 7.39-7.25 (m, 6H), 7.25-7.13 (m, 2H), 7.09 (d, J=7.2 Hz, 1H), 7.02 (d, J=7.6 Hz, 1H), 4.33 (d, J=12.6 Hz, 1H), 4.21-3.91 (m, 1H), 3.64 (dd, J=22.1, 9.9 Hz, 1H), 3.38-2.83 (m, 1H), 2.64 (s, 1H), 2.26 (s, 2H), 1.82 (d, J=43.9 Hz, 1H), 1.44 (s, 1H), 1.05 (t, J=7.0 Hz, 1H), 0.96 (dd, J=12.5, 6.4 Hz, 3H), 0.73 (s, 1H), 0.61 (t, J=7.3 Hz, 3H). LCMS: m/z=474 (M+H)⁺. Compound 026 (S): (27 mg, 27%). ¹H NMR (500 MHz, DMSO) δ 10.94 (s, 1H), 8.97 (s, 1H), 8.60 (s, 1H), 8.30 (s, 1H), 8.18 (d, J=6.5 Hz, 1H), 7.39-7.25 (m, 6H), 7.19 (dt, J=14.9, 8.7 Hz, 2H), 7.08 (t, J=7.2 Hz, 1H), 7.02 (d, J=7.5 Hz, 1H), 4.33 (d, J=13.6 Hz, 1H), 4.14-3.97 (m, 1H), 3.64 (dd, J=21.8, 10.0 Hz, 1H), 3.02-2.86 (m, 1H), 2.63 (d, J=11.8 Hz, 1H), 2.24 (d, J=12.9 Hz, 2H), 1.91-1.70 (m, 1H), 1.44 (s, 1H), 0.96 (dd, J=12.6, 6.4 Hz, 3H), 0.73 (s, 1H), 0.61 (t, J=7.4 Hz, 3H). LCMS: m/z=474 (M-FH)⁺.

Example 27 Synthesis of (R)—N-hydroxy-2-((4-methyl-1-(2-phenylpropanoyl)piperidin-4-yl)amino)pyrimidine-5-carboxamide (Compound 027)

Step 1:

Lithium bis(trimethylsilyl)amide (1.0 M solution in THF, 240 mL, 240 mmol) was slowly added to a round-bottomed flask with compound 1 (25 g, 120 mmol) at −76° C. under N₂. The reaction was stirred for 4 h at −76° C. Then iodomethane (15 ml, 240 mmol) was added into the system. The reaction mixture was stirred at −76° C. for 30 min and then warmed to room temperature overnight. The resulting mixture was quenched with 150 ml saturated aqueous NH₄Cl, diluted with water, and extracted with EtOAc. The organic layers were washed with water and brine then dried over sodium sulfate, filtered and concentrated to afford the target compound 2 (25 g, 93%) as a white solid.

Step 2:

K₂CO₃ (31 g, 223 mmol) was added to the solution of the compound 2 (25 g, 111 mmol) in DMSO (120 mL). Then H₂O₂ (100 mL) was slowly added to the reaction dropwise at 60° C. The reaction was stirred overnight at 60° C. After completion, cold water was added and the mixture was extracted with EA. The organic layers were washed with water and brine, and dried over sodium sulfate, filtered and concentrated to afford the target, compound 3, (26 g, 96%) as a white solid.

Step 3:

Compound 3 (26 g, 107 mmol) was dissolved with CH₃CN (200 mL) and 2N KOH (100 mL). Then 1,3-dibromo-5,5-dimethylimidazolidine-2,4-dione (15 g, 54 mmol) was added to the reaction and stirred overnight. Then the reaction pH was adjusted to 5 with 2N HCl and extracted with EA to remove the impurity. The aqueous phase was adjusted to a pH of 10. The precipitate was collected to afford the desired product as a white solid (16 g, 69%).

Step 4:

The solution of compound 4 (2 g, 9.34 mmol), ethyl 2-chloropyrimidine-5-carboxylate (2.6 g, 14.02 mmol) and DIPEA (5.3 g, 28.03 mmol) in 1,4-dioxane (25 mL) was heated at 95° C. overnight. Concentration and purification by a silica gel column with EA/PE=1/5 afforded compound 5 (1.8 g, 53%) as a light yellow solid.

Step 5:

To a solution of compound 5 (150 mg, 0.41 mmol) in DCM (3 ml) was added TFA (3 ml) at r.t. The reaction was stirred for 30 min. and The resulting mixture was concentrated to afford compound 6 without further purification (108 mg, 100%).

Step 6:

To a solution of compound 6 (108 mg, 0.41 mmol) and (R)-2-phenylpropanoic acid (61.5 mg, 0.41 mmol) in 5 ml DCM was added 2 ml TEA. The mixture was stirred at r.t. for 2 h and LCMS was used to monitor the reaction to completion. The target compound 7 (100 mg, 62%) was purified by filtration through silica gel.

Step 7:

To a solution of compound 7 (100 mg, 0.25 mmol) in 5 ml CH₃OH/CH₂Cl₂ was slowly added NH₂OH (1 ml) at 0° C. followed by stirring for 10 min. NaOH/CH₃OH (2 ml) was added into the solution slowly then stirred for 2 h. After removing the solvent from the solution, the pH was adjusted to 6 by 2N HCl. The target compound, Compound 027 (62 mg, 62%) was purified by Pre-HPLC to yield a white solid. ¹H NMR (500 MHz, DMSO) δ 11.04 (s, 1H), 8.58 (d, J=10.3 Hz, 2H), 7.48-7.41 (m, 1H), 7.36-7.16 (m, 5H), 4.10 (dq, J=20.4, 6.8 Hz, 1H), 3.96 (dd, J=47.4, 13.4 Hz, 1H), 3.57 (dd, J=37.9, 13.8 Hz, 1H), 3.22 (t, J=11.3 Hz, 0.5H), 3.05-2.86 (m, 1.5H), 2.27 (t, J=15.7 Hz, 1H), 2.02 (t, J=14.7 Hz, 1H), 1.46 (ddd, J=28.7, 17.1, 7.1 Hz, 1H), 1.37 (s, 1H), 1.30-1.20 (m, 3H), 1.18 (s, 0.5H), 1.17 (s, 1H), 0.56 (t, J=10.4 Hz, 0.5H). LCMS: m/z=384 (M+H)±.

Example 28 Synthesis of 2-((1-(2-(1H-indol-3-yl)acetyl)-4-phenylpiperidin-4-yl)amino)-N-hydroxypyrimidine-5-carboxamide (Compound 028)

Step 1:

To a solution of compound 7 (100 mg, 0.25 mmol) and 2-(1H-indol-3-yl)acetic acid (44 mg, 0.25 mmol) in 5 ml DMF was added HOAT (68 mg, 0.50 mmol), EDCI (78 mg, 050 mmol) and DIPEA (129 mg, 1 mmol). The mixture was stirred at 60° C. for overnight. LCMS was used to monitor the reaction to completion. The target compound 8 (90 mg, 75%) as a yellow solid was obtained by filtration through silica gel after extraction by EA.

Step 2:

To a solution of compound 8 (90 mg, 0.19 mmol) in 5 ml CH3OH/CH2Cl2 was added NH2OH (0.2 ml) slowly at 0° C., then stirred for 10 min, NaOH/CH3OH (0.5 mL) was added into the solution slowly then stirred for 2 hrs, After removing the solvent from the solution, the PH was adjusted to 6 by 2N HCl. The target compound, Compound 028 (9 mg, 10%) was purified by Pre-HPLC to yield a white solid. ¹H NMR (500 MHz, DMSO) δ 10.92 (d, J=11.9 Hz, 2H), 8.60 (s, 1H), 8.31 (s, 1H), 8.16 (s, 1H), 7.59 (d, J=7.9 Hz, 1H), 7.34 (d, J=8.1 Hz, 1H), 7.20 (dd, J=18.3, 10.7 Hz, 3H), 7.10 (dd, J=14.2, 7.4 Hz, 4H), 6.98 (t, J=7.4 Hz, 1H), 4.33 (d, J=13.1 Hz, 1H), 3.94-3.86 (m, 1H), 3.84 (s, 1H), 3.78 (s, 1H), 3.23 (t, J=12.3 Hz, 1H), 2.84 (t, J=12.3 Hz, 1H), 2.36 (s, 1H), 1.66 (s, 1H), 1.40 (s, 1H).). LCMS: m/z=471 (M+H)±.

Examples 29-30 Synthesis of (S) and (R)N-hydroxy-2-((1-(4-methyl-2-phenylpentanoyl)-4-phenylpiperidin-4-yl)amino)pyrimidine-5-carboxamide (Compounds 029 and 030)

Step 1:

To a solution of 2-phenylacetic acid (250 mg, 1.84 mmol) in THF (3 mL) was added LHDMS (4 mL, 4 mmol) at 0° C. under N₂. The reaction was stirred for 15 min, then 1-iodo-2-methylpropane (0.23 mL, 2.02 mmol) was added into the solution and stirred at r.t. overnight. After completion, water was added and the mixture was extracted with EA. The target compound 2 (335 mg, 95%) was obtained as a white solid following purification by a silica gel column.

Step 2:

To a solution of compound 2 (188 mg, 0.98 mmol) and ethyl 2-(4-phenylpiperidin-4-ylamino)pyrimi-dine-5-carboxylate (400 mg, 0.98 mmol) in 5 ml DMF was added HOAT (267 mg, 1.96 mmol), EDCI (304 mg, 1.96 mmol) and DIPEA (507 mg, 3.93 mmol). The mixture was stirred at 60° C. overnight. LCMS was used to monitor the reaction to completion. The target compound 3 (220 mg, 75%) was purified by silica gel column with EA/PE=1/2. Compound 3 was isolated from Chiral-HPLC to afford compound R- (90 mg, 41%) and compound S- (90 mg, 41%).

Step 3: To a solution of compounds from the above step (90 mg, 0.18 mmol) in 5 ml CH₃OH/CH₂Cl₂ was slowly added NH₂OH (0.2 ml) at 0° C., followed by stirring for 10 min. NaOH/CH₃OH (0.4 ml) was slowly added to the solution and then stirred for 2 h. After removing the solvent, the pH was adjusted to 6 by 2N HCl. The target compound was purified by Pre-HPLC: Compound 29 (S) (60 mg, 68%). ¹H NMR (500 MHz, DMSO) δ 10.91 (s, 1H), 8.96 (s, 1H), 8.55 (s, 1H), 8.31 (s, 1H), 8.14 (d, J=18.9 Hz, 1H), 7.44-7.23 (m, 6H), 7.13 (ddd, J=30.2, 19.8, 8.3 Hz, 2H), 7.01-6.95 (m, 2H), 4.34 (s, 1H), 4.11-3.91 (m, 2H), 2.84 (ddd, J=47.4, 25.9, 12.5 Hz, 1H), 2.72-2.56 (m, 1H), 2.50 (s, 1H), 2.23 (d, J=11.3 Hz, 0.5H), 1.90-1.79 (m, 2H), 1.75-1.30 (m, 2.5H), 0.94-0.74 (m, 6H), 0.72 (s, 1H). LCMS: m/z=488 (M+H)⁺. Compound 030 (R) (60 mg, 68%): ¹HNMR NMR (500 MHz, DMSO) δ 10.96 (s, 1H), 8.98 (s, 1H), 8.61 (s, 1H), 8.31 (s, 1H), 8.18 (d, J=19.3 Hz, 1H), 7.43-7.00 (m, 10H), 4.35 (d, J=12.0 Hz, 1H), 4.15-3.99 (m, 1H), 3.95 (d, J=13.1 Hz, 0.5H), 3.29 (d, J=12.5 Hz, 0.5H), 2.90 (dt, J=24.4, 12.5 Hz, 1H), 2.59 (dd, J=30.5, 16.2 Hz, 1H), 2.23 (d, J=12.9 Hz, 0.5H), 1.94-1.74 (m, 1.5H), 1.54-1.31 (m, 2.5H), 0.95-0.79 (m, 6H), 0.72 (t, J=11.1 Hz, 0.5H). LCMS: m/z=488 (M+H)⁺.

Example 31 Synthesis of 2-((1-(2-(1H-indol-2-yl)acetyl)-4-phenylpiperidin-4-yl)amino)-N-hydroxypyrimidine-5-carboxamide (Compound 031)

Step 1:

To a solution of compound 7 (100 mg, 0.25 mmol) and 2-(1H-indol-2-yl)acetic acid (44 mg, 0.25 mmol) in 5 ml DMF was added HOAT (68 mg, 0.50 mmol), EDCI (78 mg, 0.50 mmol) and DIPEA (129 mg, 1 mmol). The mixture was stirred at 60° C. overnight, LCMS monitored the reaction to completion. The target compound 8 (80 mg, 766%) was obtained as a yellow solid following extraction with EA and filtration through silica gel.

Step 2:

To a solution of compound 8 (80 mg, 0.17 mmol) in 5 ml CH₃OH/CH₂Cl₂ was slowly added NH2OH (0.2 ml) at 0° C. followed by stirring for 10 min. NaOH/CH3OH (0.4 ml) was added to the solution slowly and stirred for 2 h. After removing the solvent from the solution, the PH was adjusted to 6 by 2N HCl. Purified by Pre-HPLC yielded the target compound, Compound 031, (9 mg, 10%) was as a white solid. ¹H NMR (500 MHz, DMSO) δ 10.94 (s, 2H), 8.61 (s, 1H), 8.32 (s, 1H), 8.24 (s, 1H), 7.42 (d, J=7.7 Hz, 1H), 7.31 (d, J=7.3 Hz, 3H), 7.24 (t, J=7.7 Hz, 2H), 7.14 (t, J=7.2 Hz, 1H), 7.00 (t, J=7.1 Hz, 1H), 6.92 (t, J=7.2 Hz, 1H), 6.20 (s, 1H), 4.34 (d, J=13.4 Hz, 1H), 3.92 (d, J=16.1 Hz, 2H), 3.34 (t, J=12.0 Hz, 1H), 2.91 (t, J=12.6 Hz, 1H), 2.64 (s, 1H), 1.88-1.70 (m, 2H). LCMS: m/z=471 (M+H)⁺.

Example 32 HDAC Enzyme Assays

Compounds for testing were diluted in DMSO to 50 fold the final concentration and a ten point three fold dilution series was made. The compounds were diluted in assay buffer (50 mM HEPES, pH 7.4, 100 mM KCl, 0.001% Tween-20, 0.05% BSA, 20 μM TCEP) to 6 fold their final concentration. The HDAC enzymes (purchased from BPS Biosciences) were diluted to 1.5 fold their final concentration in assay buffer. The tripeptide substrate and trypsin at 0.05 μM final concentration were diluted in assay buffer at 6 fold their final concentration. The final enzyme concentrations used in these assays were 3.3 ng/ml (HDAC1), 0.2 ng/ml (HDAC2), 0.08 ng/ml (HDAC3) and 2 ng/ml (HDAC6). The final substrate concentrations used were 16 μM (HDAC1), 10 μM (HDAC2), 17 μM (HDAC3) and 14 μM (HDAC6).

Five μl of compounds and 20 μl of enzyme were added to wells of a black, opaque 384 well plate in duplicate. Enzyme and compound were incubated together at room temperature for 10 minutes. Five μl of substrate was added to each well, the plate was shaken for 60 seconds and placed into a Victor 2 microtiter plate reader. The development of fluorescence was monitored for 60 min and the linear rate of the reaction was calculated. The IC₅₀ was determined using Graph Pad Prism by a four parameter curve fit. The IC₅₀ values obtained for several of the compounds of this invention are found in Table 1.

Example 33 Pharmacological Inhibition of Histone Deacetylase (HDAC) 1, 2 or 3 have Distinct Effects on Cellular Viability, Erythroid Differentiation, and Fetal Globin (HbG) Induction

In this example, the effects of selective inhibitors of HDAC1, 2, or 3, on cytoxicity, erythroid differentiation, and HbG induction in cultured human CD34+ bone marrow cells was investigated.

A prior compound, Compound A, is a class I HDAC inhibitor with IC₅₀ values of 5, 5, and 8 nM against HDAC1, 2, and 3, respectively (i.e., it is a non-selective HDAC inhibitor). Compound 001 is 30-fold selective for HDAC1 and 2, with IC₅₀ values of 38, 34, and 1010 nM against HDAC1, 2, and 3, respectively. Treatment of cells for 4 days with Compound A (1 μM) resulted in a 20-fold decrease in cells viability, while treatment with Compound 001 (1 μM) resulted in a minimal reduction in viability (1.2-fold) and a 2-fold increase in the percentage of HbG relative to other beta-like globin transcripts (see FIG. 1). This result suggests that pharmacological inhibition of HDAC3 is cytotoxic and is consistent with the therapeutic rationale for the design of selective inhibitors of HDAC1 and 2.

Example 34 Evaluation of Test Compounds on Human Erythroid, Myeloid and Megakaryocyte Hematopoietic Progenitor Proliferation in Media Formulations Containing Various Cytokines

This study evaluated the potential effect of test compounds on human erythroid, myeloid and megakaryocyte hematopoietic progenitor proliferation in media formulations containing various cytokines. Normal human bone marrow light density cells derived from a normal bone marrow donor (Lonza, Md.) were used for these studies. Clonogenic progenitors of human erythroid (CFU-E, BFU-E) and granulocyte-monocyte (CFU-GM) lineages were assessed in a semi-solid methylcellulose-based media formulation containing rhIL-3 (10 ng/mL), rhGM-SCF (10 ng/mL), rhSCF (50 ng/mL) and Epo (3 U/mL). Clonogenic progenitors of human megakaryocyte lineage were assessed in a semi-solid collagen based matrix containing rhIL-3 (10 ng/mL), rhIL-6 (10 ng/mL) and rhTpo (50 ng/mL).

Compounds were added to the medium to give the final desired concentrations. Solvent control cultures (containing no compound but 0.1% DMSO) as well as standard controls (containing no compound and no DMSO) were also initiated for both media formulations. Human myeloid and erythroid progenitor assays were initiated at 2.5×10⁴ cells per culture and human megakaryocyte progenitor assays were initiated with 1×10⁵ cells per culture. Following 14-16 days in culture, myeloid and erythroid colonies were assessed microscopically and scored by trained personnel. The colonies were divided into the following categories, based on size and morphology; CFU-E, BFU-E, and CFU-GM. For the human megakaryocyte assay, the cultures were transferred from the 35 mm dishes to labeled glass slides, were fixed (methanol/acetone) and then stained using an anti-human CD41 antibody and an alkaline phosphate detection system according to manufactures' instructions. The colonies were assessed and scored by trained personnel and divided into the following categories based on size; CFU-Mk (3-20), CFU-Mk (21-49) and CFU-Mk (≧50).

The mean±1 standard deviation of three replicate cultures was calculated for progenitors in both media formulations. To calculate the concentration of 50% inhibition of colony growth (IC₅₀) for each compound, a dose response curve was generated plotting the log of the compound concentration versus the percentage of control colony growth using Origin® 8. A sigmoidal curve was then fit to the graph and from this curve the inhibitory concentration (μM) was then calculated using the Boltzman equation

$y = {\left\lbrack \frac{A_{1} - A_{2}}{1 + ^{(\frac{x - x_{0}}{dx})}} \right\rbrack + A_{2}}$

where A₁=the initial value (baseline response), A₂=0 (maximum response), x₀=center (drug concentration that provokes a response halfway between A₁ and A₂) and dx=slope of the curve at midpoint as determined by Origin® 8. Results are shown in FIGS. 2A-F.

This example demonstrates that Compound-001, an HDAC1,2-selective compound, has significantly less cytotoxicity against erythroid, myeloid and megakaryocytes than does MS-275, an HDAC1,2,3-selective compound. These results suggest that selective inhibition of HDAC1 and 2 using Compound-001 may result in significantly less in vivo cytotoxicity in the hematopoietic compartment than pan-HDAC inhibitors.

Example 35 In Vitro Cell Proliferation

H929 human myeloma cells were seeded in 96-well plates and grown in the presence of increasing levels of Compound 001 for a period up to 7 days. Cellular viability was assessed using Aqueous One MTS reagent at Days 0 (immediately after seeding), 3, 5, and 7. FIG. 3A shows dose-response curves for Compound 001 at Day 0, Day 3, Day 5, and Day 7, with the half-maximal dose (IC₅₀) at each day indicated by a dashed line. FIG. 3B shows the relative growth of H929 cells over time in the absence of drug as well as in the presence of increasing doses of Compound 001. The dashed line indicates the level of viability at Day 0, thus doses over 3 uM resulted in a net decrease in the viability of H929 cells.

Example 36 Synthesis of N-(2-amino-5-(thiophen-2-yl)phenyl)-2-cyclopropyl-1-(2-morpholinoethyl)-1H-indole-5-carboxamide (Compound X)

Reaction Scheme

Experimental Procedure

Step 1:

To a solution of compound 1 in DCE was added POBr₃ and imidazole. The reaction was stirred at 80° C. overnight. Water and DCM were added to the reaction, and the organic layer was separated, washed with brine, and dried under reduced pressure to give compound 2.

Step 2:

To a solution of compound 2 in DMSO was added compound a and KOH. The resulting reaction mixture was stirred at 45° C. for 4 h, quenched with H₂O, and extracted with EA. The combined organic layers were purified by gel chromatography to yield the desired product, compound 3.

Step 3:

A mixture of compound 3, cyclopropyl boronic acid, Pd(OAc)₂, tricyclohexylphosphine, and K₃PO₄ in toluene and water was stirred at 100° C. under N₂ atmosphere overnight. The mixture was cooled, filtered, and concentrated to obtain a residue, which was purified by Prep-TLC to get compound 4.

Step 4:

A mixture of compound 4 and NaOH in EtOH and THF was stirred at 60° C. for 5 h. The mixture was concentrated to obtain a residue, to which was added aq. sat. citric acid and extracted with EA. The organic layers were separated, dried, filtered and concentrated to obtain compound 5.

Step 5:

A mixture of compound 5, tert-butyl 2-amino-4-(thiophen-2-yl)phenylcarbamate, HOAT, EDCI, and DIPEA in DMF was stirred at 55° C. for overnight. Water was added to the mixture, and extracted with EA. The organic layers were separated, dried, filtered, and concentrated to get a residue, which was purified by Prep-TLC to afford compound 6.

Step 6:

To a solution of compound 6 in DCM was added TFA and stirred at r.t. for 1 h. The mixture was concentrated to obtain a residue, which was purified by Prep-HPLC to afford compound 7. ¹H NMR (500 MHz, DMSO) δ 9.63 (s, 1H), 8.16 (s, 1H), 7.79-7.73 (m, 1H), 7.51 (d, J=2.1 Hz, 2H), 7.36 (d, J=5.1 Hz, 1H), 7.29 (dd, J=8.3, 2.1 Hz, 1H), 7.25 (d, J=3.5 Hz, 1H), 7.05 (dd, J=5.0, 3.6 Hz, 1H), 6.82 (d, J=8.3 Hz, 1H), 6.24 (s, 1H), 5.12 (s, 2H), 4.43 (s, 2H), 3.57 (s, 5H), 2.77-2.58 (m, 2H), 2.09 (s, 1H), 1.02 (d, J=8.0 Hz, 2H), 0.76 (d, J=4.4 Hz, 2H). LCMS: m/z=487.2 (M+H)+.

Table 2 below shows the IC₅₀ (nM) of Compound X for HDACs 1, 2, and 3.

TABLE 2 Compound HDAC1 HDAC2 HDAC3 Compound X 6 36 445

Example 37 HDAC1/2/6 Selective Inhibitor Blocks Neuroblastoma Migration

Many cultured cancer cells are able to migrate across a membrane and this activity indicates the metastatic potential of the cancer cells. The migration of neuroblastoma cell line SK-N-SH was compared in the presence or absence of Compound 001, a HDAC1/2/6 inhibitor. The cancer cells were seeded and grown on a membrane surface, and the cell numbers on the other side of the membrane were counted under a microscope after 12 hours. A decreased number of migrated cells by the HDAC1/2/6 inhibitor suggests a migration suppression activity of HDAC1/2/6 inhibitor. In the study, an HDAC inhibitor was added to the cells either 2 hours before or when the migration was measured. The effect of HDAC1/2/6 inhibitor on Epidermal Growth Factor (EGF) stimulated cancer cell migration using 40 ng/ml of EGF in the assay was investigated.

The protocol for the migration assay was as follows. The compounds were prepared in DMSO at 400× stock of the final required concentrations. See Table 3.

TABLE 3 Compound Final conc. (μM) Cpds 400* Conc. (μM) Compound 001 0.5 200 Gefitinib 1 400 EGF 20 8 200 μl of warm basal RPMI1640 medium was added to the interior of the inserts, allowed to rehydrate for 2 hours in a humidified tissue culture incubator at 37° C., 5% CO₂ atmosphere. During rehydration, the cells were harvested with trypsin, washed 3 times, and then resuspended with pre-warmed basal RPMI1640 medium containing 500,000 cells/ml or 250,000 cells/ml. The compounds were diluted to 20× with basal RPMI1640 medium. 25 μl of 20× compound was added to the 500 μl cell suspension to make the final cell suspension with compound. 100 μl of 20× compound was added to 1,900 μl RPMI1640 medium with 10% FBS to get the final medium, and 500 μl of the final medium was added to the well a new 24-well plate. After rehydration, the medium was removed from the inserts, and then 100 μl final cell suspension was added to the chambers. The chambers were transferred to the wells containing final medium. 100 μl/well of final cell suspension (diluted with final medium to 1/2 density) was added to a 96-well plate (triplicate). After 8 hours incubation at 37° C., the non-invading cells were removed from the upper surface of the membrane with cotton swabs. Cells on the lower surface of the membrane were fixed with 4% paraformaldehyde for 15 minutes at room temperature, and then stained with crystal violet for 30 minutes. After staining, the inserts were washed in PBS several times to ensure that there was no crystal violet on the membrane, except the cells. The number of migrated cells were counted under a microscope in five fields at 100× magnification. The viable cells were seeded in the 96 well plate with the same treatment as in the migration assay were measured using CTG (Cell Titer Glow).

The results of these experiments are shown in FIGS. 4A-C.

Example 38 HDAC1/2 Selective Inhibitors Induce Neuroblastoma Maturation

The following is a quick summary of the HDAC neuroblastoma maturation experiments. Adherent cells were plated into 12- or 24-well plates at 10⁶ cells/well and allowed to adhere for 2-4 hours. Compounds were dispensed in DMSO at the indicated concentrations using an automated liquid handling system (Tecan D300) and incubated for the indicated times at 37° C. with 5% CO₂. Cells were harvested and RNA extracted using the Qiagen RNeasy Mini Kit according to manufacture protocols. The RNA was quantified and relative expression levels were assessed using the Applied Biosystems Taq Man RNA-to-Ct Kit according to manufacture protocols using the indicated Taq Man probes.

The protocol for the maturation experiments was as follows. The day before the experiment, the cells were fed in the flask by doubling the media. The cells were then harvested by adding non-enzymatic cell dissociation media and incubating at 37° C. for 15 minutes. The cells were transferred to a 50 ml tube and pipet to create a single-cell suspension. The cells were washed with PBS buffer. The cells were then resuspended in complete media at 5×10⁵ cells per ml. Next, 2 ml of cells were transferred to 24- or 12-well plates. The treatment compounds were then dispensed into each well using the D300 liquid handler. The cells were then incubated for the indicated time at 37° C. The cells were harvested by scraping the cells and transferring to a 2 ml tube. The cells were spun to form a pellet. Next, RNA was extracted using the Qiagen RNeasy Mini kit according to manufacture protocols. The RNA concentration was recorded. The relative RNA levels were assessed using the Applied Biosystems Taq Man RNA-to-Ct kit according to manufacture protocols using the indicated Taq man probes.

In one set of experiments, BE(2)-C neuroblastoma cells were treated for 4 days with Compound X at 0.5 μM (FIG. 5A), 1 μM (FIG. 5B), and 3 μM (FIG. 5C). Each of the experiments measured the fold change of various genes associated with maturation, such as TGM2, KCTD13, EGR1, JARID2, MAFF, p21, DUSP6, DDAH2, CRABP2, SLC29A1, KCTD12, ASCL1, and GATA3. FIG. 5D shows the results of a positive control experiment in which BE(2)-C cells were treated for 4 days with 1 μM ATRA (all trans retinoic acid). FIG. 5E shows the results of a negative control experiment in which BE(2)-C cells were treated with 1 μM of a HDAC6 selective inhibitor. The results of these experiments show that Compound X, a HDAC1/2 selective inhibitor, alters genes associated with maturation. The strongest effects were seen at 3 μM of compound.

In another set of experiments, SH-SY5Y neuroblastoma cells were treated for 72 hours with 1 μM ATRA (all trans retinoic acid) (FIG. 6A), a HDAC6 selective inhibitor (FIG. 6B), Compound X (FIG. 6C), and another HDAC6 selective inhibitor (FIG. 6D). Each of the experiments measured the fold change of various genes associated with maturation, such as HOXD4, ADD3, p21, DDAH2, IGBFP5, PPIF, GATA3, CHGA, and ASCL1. Table 4 below shows the IC₅₀s in nM of the various compounds.

TABLE 4 HDAC1 HDAC2 HDAC3 HDAC6 HDAC6i 2123 2570 11223 7 another HDAC6i 33 54 61 5 Compound X 6 36 445 — The results of these experiments show that Compound X, a HDAC1/2 selective inhibitor, alters genes associated with maturation.

In yet another set of experiments, BE(2)-C neuroblastoma cells were treated for 72 hours with 1 μM ATRA (all trans retinoic acid) (FIG. 7A), a HDAC6 selective inhibitor (FIG. 7B), Compound X (FIG. 7C), and another HDAC6 selective inhibitor (FIG. 7D). Each of the experiments measured the fold change of various genes associated with maturation, such as HOXD4, ADD3, p21, DDAH2, IGBFP5, PPIF, GATA3, CHGA, and ASCL1. Table 5 below shows the IC₅₀s in nM of the various compounds.

TABLE 5 HDAC1 HDAC2 HDAC3 HDAC6 HDAC6i 2123 2570 11223 7 another HDAC6i 33 54 61 5 Compound X 6 36 445 — The results of these experiments show that Compound X, a HDAC1/2 selective inhibitor, alters genes associated with maturation.

In another set of experiments, the fold change of genes associated with maturation were assessed. In one experiment, BE(2)-C neuroblastoma cells were treated for 2 days with 3 μM Compound 001 (FIG. 8A). In a second experiment, SH-SY5Y neuroblastoma cells were treated for 2 days with 3 μM Compound 001 (FIG. 8B). In a third experiment, BE(2)-C neuroblastoma cells were treated for 2 days with 3 μM Compound X (FIG. 8C). Each of the experiments measured the fold change of various genes associated with maturation, such as p21, CRABP2, JARID2, KCTD13, TGM2, ASCL1, and GATA3. The results of these experiments show that Compound 001, a HDAC1/2/6 selective inhibitor, induces gene expression changes that are consistent with maturation.

In a set of experiments, BE(2)-C neuroblastoma cells were treated for 48 hours with Compound 001 at 0.5 μM (FIG. 9A), 2 μM (FIG. 9B), and 4 μM (FIG. 9C). FIG. 9D shows the results of a positive control experiment in which BE(2)-C cells were treated for 48 hours with 1 μM ATRA (all trans retinoic acid). Each of the experiments measured the fold change of various genes associated with maturation, such as VGF, TGM2, SYT11, RBP1, MAFF, JARID2, PTK2, HOXD4, EGR1, DUSP6, DDAH2, CRABP2, ADDS, SLC29A1, PPIF, KCTD12, IGFBP5, GATA3, CHGA, and ASCL1. The results of these experiments show that Compound 001 induces gene expression changes consistent with maturation at 4 μM, but not at 2 μM or less. HDAC2glo assay data suggest maximal HDAC2 inhibition was reached at 3-4 μM.

A set of experiments shows that a HDAC3 selective inhibitor fails to modulate genes associated with maturation. BE(2)-C neuroblastoma cells were treated for 4 days with a HDAC3 selective inhibitor at 1 μM (FIG. 10A), 0.5 μM (FIG. 10B), and 3 μM (FIG. 10C). Each of the experiments measured the fold change of various genes associated with maturation, such as EGR1, CRABP2, DUSP6, p21, DDAH2, ASCL1, GATA3, IGFBP5, KCTD12, and SLC29A1. FIG. 10D shows the results of a positive control experiment in which BE(2)-C neuroblastoma cells were treated for 4 days with 1 μM ATRA (all trans retinoic acid). FIG. 10E shows the results of a negative control experiment in which BE(2)-C neuroblastoma cells were treated for 4 days with 1 μM of a HDAC6 selective inhibitor. The results of these experiments show that a HDAC3 selective inhibitor did not alter gene expression in a manner consistent with neuroblastoma maturation. In addition, the dose response was modest, if present at all.

A set of experiments shows that a HDAC6 selective inhibitor fails to modulate genes associated with maturation. BE(2)-C neuroblastoma cells were treated for 48 hours with HDAC6 selective inhibitor at 0.5 μM (FIG. 11A), 2 μM (FIG. 11B), and 4 μM (FIG. 11C). FIG. 11D shows the results of a positive control experiment in which BE(2)-C neuroblastoma cells were treated for 48 hours with 1 μM ATRA (all trans retinoic acid). Each of the experiments measured the fold change of various genes associated with maturation, such as VGF, TGM2, SYT11, RBP1, MAFF, JARID2, PTK2, HOXD4, EGR1, DUSP6, DDAH2, CRABP2, ADD3, SLC29A1, PPIF, KCTD12, IGFBP5, GATA3, CHGA, and ASCL1. The results of these experiments show that a HDAC6 selective inhibitor failed to robustly induce gene changes consistent with maturation, even at 4 μM of exposure. These results are consistent with a previous experiment where maturation was not evident after 1 μM of treatment.

Example 39 HDAC1/2 Inhibition Induces Increased Sub-G1 Cell Populations at a Concentration where Maturation is Occurring

The following is a quick summary of the neuroblastoma cell cycle experiments. Adherent cells were plated into 12-well plates at 10⁶ cells/well and allowed to adhere for 2-4 hours. Compounds were dispensed in DMSO at the indicated concentrations using an automated liquid handling system (Tecan D300) and incubated for the indicated times at 37° C. with 5% CO₂. Cells were harvested with enzyme-free cell disassociation solution and washed with buffered saline. Cells were fixed overnight with 100% ethanol. Cell cycle was assessed by flow cytometry using the Molecular Probes FxCycle PI/RNase Staining Solution kit according to manufacture protocols.

The protocol for the cell cycle experiments was as follows. The day before the experiment, the cells were fed in the flask by doubling the media. Then, the cells were harvested by adding non-enzymatic cell dissociation media and incubating at 37° C. for 15 minutes. Next, the cells were transferred to a 50 ml tube and pipet to create a single-cell suspension. The cells were then washed with PBS buffer. Then, the cells were resuspended in complete media at 5×10⁵ cells per ml. Next, 2 ml of cells were transferred to 12-well plates. Then, the treatment compounds were dispensed into each well using the D300 liquid handler. The cells were incubated for the indicated time at 37° C. Then, the cells were harvested by adding 500 μl enzyme free cell dissociation solution and incubating at 37° C. for 15 minutes. Next, the cells were spun into a pellet and then washed with PBS. Then, 500 μl 100% EtOH was added and incubated at 4° C. overnight. Then, the cells were washed 3× with PBS. The cells were then resuspended in 500 ml FxCycle PI/RNase solution, and incubated for 2-4 hours at room temperature. Finally, the cells were assayed by flow cytometry.

This set of experiments shows that selective HDAC inhibition alters cell cycle progression in neuroblastoma cells. In a first experiment, SH-SY5Y neuroblastoma cells were treated for 72 hours with 0, 0.5, 2, and 5 μM of a HDAC6 selective inhibitor (FIG. 12A). In a second experiment, SH-SY5Y neuroblastoma cells were treated for 72 hours with 0, 0.5, 2, and 5 μM Compound X (FIG. 12B). In a third experiment, SH-SY5Y neuroblastoma cells were treated for 72 hours with 0, 0.5, 2, and 5 μM Compound 001 (FIG. 12C). In a control experiment, SH-SY5Y neuroblastoma cells were treated for 72 hours with 0 and 1 μM ATRA (all trans retinoic acid) (FIG. 12D). Each of the experiments looked at the percent of the cell population in the G2 phase, S phase, G1 phase, and Sub G1 phase. The results of this experiment show that Compound 001 induced a reduction in G1/G2 and increase in sub-G1 at concentrations where maturation was observed. Also, Compound X induced similar cell cycle changes in all treatment groups, even at low doses associated with sub-optimal maturation. In addition, a HDAC6 selective inhibitor induced a dose-dependent decrease in G1/G2 with a corresponding increase in sub-G1. Finally, ATRA had little impact on cell cycle at concentrations associated with robust maturation at this time point.

Example 40 HDAC Inhibition Decreases Neuroblastoma Viability and Survival

SK-N-BE(2) or SH-SY5Y neuroblastoma cells were treated with varying concentrations of either Compound X or Compound Y. Viability and the Caspase 3/7 Signal were measured at 48 hours. The percentage of the population of the cells at various stages of the cell cycle were measured at 96 hours. See FIGS. 13A-D and FIGS. 14A-D. The results of these experiments show that low levels of apoptosis and cell death were detected at 48 hours after HDACi, the time when gene expression changes associated with differentiation were observed. An increase in the sub-G1 population became evident at 96 hours after treatment, indicating cell death at later times.

Example 41 HDAC Inhibition Drives Neuroblastoma Differentiation

SK-N-BE(2) or SH-SY5Y neuroblastoma cells were treated with varying concentrations of either Compound X or Y, and/or ATRA (all trans retinoic acid). The differentiation index was measured. See FIGS. 15A-D. The results of these experiments show that both Compound X and Compound Y induced an increase in the differentiation index, and the effect was markedly enhanced when an HDACi was combined with retinoic acid.

Example 42 HDAC Inhibition Enhances Low-Concentration ATRA

SK-N-BE(2) or SH-SY5Y neuroblastoma cells were treated with varying concentrations of either Compound X or Y, and/or ATRA (all trans retinoic acid). The differentiation index was measured. As a control, SK-N—BE(2) or SH-SY5Y neuroblastoma cells were treated with varying concentrations of ATRA. See FIGS. 16A-C. The results of these experiments show that ATRA differentiation was sub-optimal at 0.25 μM, and both Compound X and Compound Y potentiated 0.25 μM ATRA.

Example 43 HDAC Inhibition Induce Cell Cycle Arrest in Neuroblastoma Cells

SK-N-BE(2) neuroblastoma cells were treated with varying concentrations of either Compound X or Y, and/or ATRA (all trans retinoic acid). The percentage of the population of the cells at various stages of the cell cycle were measured after 4 days. In addition, the fold change of p21 was also calculated. See FIGS. 17A-D. Both Compound X and Compound Y induced cell cycle arrest, with Compound Y being the more potent agent. The HDACi/ATRA combination effects were modest, with little difference compared to single agents.

Example 44 HDAC Inhibition Induce Cell Cycle Arrest in Neuroblastoma Cells

SH-SY5Y neuroblastoma cells were treated with varying concentrations of either Compound X or Y, and/or ATRA (all trans retinoic acid). The percentage of the population of the cells at various stages of the cell cycle were measured after 4 days. In addition, the fold change of p21 was also calculated. See FIGS. 18A-D. Both Compound X and Compound Y induced cell cycle arrest, with Compound Y being the more potent agent. The HDACi/ATRA combination effects were modest, with little difference compared to single agents.

Example 45 Synthesis of 2-(diphenylamino)-N-(7-(hydroxyamino)-7-oxoheptyl) pyrimidine-5-carboxamide (Compound A)

Reaction Scheme

Synthesis of Intermediate 2:

A mixture of aniline (3.7 g, 40 mmol), compound 1 (7.5 g, 40 mmol), and K₂CO₃ (11 g, 80 mmol) in DMF (100 ml) was degassed and stirred at 120° C. under N₂ overnight. The reaction mixture was cooled to r.t. and diluted with EtOAc (200 ml), then washed with saturated brine (200 ml×3). The organic layers were separated and dried over Na₂SO₄, evaporated to dryness and purified by silica gel chromatography (petroleum ethers/EtOAc=10/1) to give the desired product as a white solid (6.2 g, 64%).

Synthesis of Intermediate 3:

A mixture of compound 2 (6.2 g, 25 mmol), iodobenzene (6.12 g, 30 mmol), CuI (955 mg, 5.0 mmol), Cs₂CO₃ (16.3 g, 50 mmol) in TEOS (200 ml) was degassed and purged with nitrogen. The resulting mixture was stirred at 140° C. for 14 hrs. After cooling to r.t., the residue was diluted with EtOAc (200 ml). 95% EtOH (200 ml) and NH₄F—H₂O on silica gel [50 g, pre-prepared by the addition of NH₄F (100 g) in water (1500 ml) to silica gel (500 g, 100-200 mesh)] was added, and the resulting mixture was kept at r.t. for 2 hrs. The solidified materials were filtered and washed with EtOAc. The filtrate was evaporated to dryness and the residue was purified by silica gel chromatography (petroleum ethers/EtOAc=10/1) to give a yellow solid (3 g, 38%).

Synthesis of Intermediate 4:

2N NaOH (200 ml) was added to a solution of compound 3 (3.0 g, 9.4 mmol) in EtOH (200 ml). The mixture was stirred at 60° C. for 30 min. After evaporation of the solvent, the solution was neutralized with 2N HCl to give a white precipitate. The suspension was extracted with EtOAc (2×200 ml), and the organic layers were separated, washed with water (2×100 ml), brine (2×100 ml), and dried over Na₂SO₄. Removal of the solvent gave a brown solid (2.5 g, 92%).

Synthesis of Intermediate 6:

A mixture of compound 4 (2.5 g, 8.58 mmol), compound 5 (2.52 g, 12.87 mmol), HATU (3.91 g, 10.30 mmol), and DIPEA (4.43 g, 34.32 mmol) was stirred at r.t. overnight. After the reaction mixture was filtered, the filtrate was evaporated to dryness and the residue was purified by silica gel chromatography (petroleum ethers/EtOAc=2/1) to give a brown solid (2 g, 54%).

Synthesis of 2-(diphenylamino)-N-(7-(hydroxyamino)-7-oxoheptyl)pyrimidine-5-carboxamide (Compound A)

A mixture of the compound 6 (2.0 g, 4.6 mmol), sodium hydroxide (2N, 20 mL) in MeOH (50 ml) and DCM (25 ml) was stirred at 0° C. for 10 min. Hydroxylamine (50%) (10 ml) was cooled to 0° C. and added to the mixture. The resulting mixture was stirred at r.t. for 20 min. After removal of the solvent, the mixture was neutralized with 1M HCl to give a white precipitate. The crude product was filtered and purified by pre-HPLC to give a white solid (950 mg, 48%).

Example 46 Synthesis of 2-((2-chlorophenyl)(phenyl)amino)-N-(7-(hydroxyamino)-7-oxoheptyl)pyrimidine-5-carboxamide (Compound Y)

Reaction Scheme:

Synthesis of Intermediate 2:

See synthesis of intermediate 2 in Example 45.

Synthesis of Intermediate 3:

A mixture of compound 2 (69.2 g, 1 equiv.), 1-chloro-2-iodobenzene (135.7 g, 2 equiv.), Li₂CO₃ (42.04 g, 2 equiv.), K₂CO₃ (39.32 g, 1 equiv.), Cu (1 equiv. 45 μm) in DMSO (690 ml) was degassed and purged with nitrogen. The resulting mixture was stirred at 140° C. Work-up of the reaction gave compound 3 at 93% yield.

Synthesis of Intermediate 4:

See synthesis of intermediate 4 in Example 45.

Synthesis of Intermediate 6:

See synthesis of intermediate 6 in Example 45.

Synthesis of 2-((2-chlorophenyl)(phenyl)amino)-N-(7-(hydroxyamino)-7-oxoheptyl)pyrimidine-5-carboxamide (Compound B)

See synthesis of Compound A in Example 45.

INCORPORATION BY REFERENCE

The contents of all references (including literature references, issued patents, published patent applications, and co-pending patent applications) cited throughout this application are hereby expressly incorporated herein in their entireties. Unless otherwise defined, all technical and scientific terms used herein are accorded the meaning commonly known to one with ordinary skill in the art.

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents of the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims. 

1. A method of selectively inhibiting the activity of HDAC1, HDAC2, and HDAC6 over other HDACs in a subject in need thereof comprising administering to the subject a compound of Formula I:

or a pharmaceutically acceptable salt thereof, wherein, R_(x) is selected from the group consisting of C₁₋₆-alkyl, C₁₋₆-alkoxy, halo, —OH, —C(O)R¹, —CO₂R¹, —C(O)N(R¹)₂, aryl, —C(S)N(R¹)₂, and S(O)₂R¹, wherein aryl may be optionally substituted by one or more groups selected from C₁₋₆-alkyl, C₁₋₆-alkoxy, —OH, halo, and haloalkyl; R_(y) is selected from the group consisting of H, C₁₋₆-alkyl, C₁₋₆-alkoxy, halo, —OH, —C(O)R¹, —CO₂R¹, and —C(O)N(R¹)₂; R_(z) is selected from the group consisting of C₁₋₆-alkyl, C₁₋₆-alkenyl, C₁₋₆-alkynyl, C₃₋₈-cycloalkyl, C₃₋₇-heterocycloalkyl, aryl, and heteroaryl, each of which may be optionally substituted by C₁₋₆-alkyl, C₁₋₆-alkoxy, halo, or —OH; and each R¹ is, independently for each occurrence, selected from the group consisting of H, C₁₋₆-alkyl, C₃₋₈-cycloalkyl, C₃₋₇-heterocycloalkyl, aryl, heteroaryl, C₁₋₆-alkyl-cycloalkyl, C₁₋₆-alkyl-heterocycloalkyl, C₁₋₆-alkyl-aryl, and C₁₋₆-alkyl-heteroaryl, wherein C₃₋₈-cycloalkyl, C₃₋₇-heterocycloalkyl, aryl, heteroaryl, C₁₋₆-alkyl-cycloalkyl, C₁₋₆-alkyl-heterocycloalkyl, C₁₋₆-alkyl-aryl, and C₁₋₆-alkyl-heteroaryl may be optionally substituted by one or more groups selected from C₁₋₆-alkyl, C₁₋₆-alkoxy, —OH, halo, and haloalkyl.
 2. The method of claim 1, wherein the compound of Formula I has the structure of Formula II:

or a pharmaceutically acceptable salt thereof, wherein, R_(x) is independently selected from the group consisting of aryl, —C(O)R¹, —CO₂R¹, —C(O)N(R¹)₂, —C(S)N(R¹)₂, and S(O)₂R¹; R_(y) is selected from the group consisting of H, C₁₋₆-alkyl, or, halo; and R_(z) is selected from the group consisting of C₁₋₆-alkyl, C₃₋₈-cycloalkyl, C₃₋₇-heterocycloalkyl, aryl, and heteroaryl.
 3. The method of claim 1, wherein R_(z) is C₁₋₆-alkyl or aryl.
 4. The method of claim 1, wherein R_(z) is isopropyl or methyl.
 5. The method of claim 1, wherein R_(z) is phenyl.
 6. The method of claim 1, wherein R_(x) is —C(O)NHR¹.
 7. The method of claim 1, wherein R_(x) is —C(O)R¹ or —CO₂R¹.
 8. The method of claim 1, wherein R_(x) is —C(S)NHR¹ or S(O)₂R¹.
 9. The method of claim 1, wherein at least one of R¹ is selected from the group consisting of C₁₋₆-alkyl, aryl, C₁₋₆-alkyl-aryl and C₁₋₆-alkyl-heteroaryl, wherein aryl, C₁₋₆-alkyl-aryl and C₁₋₆-alkyl-heteroaryl may be optionally substituted by one or more groups selected from C₁₋₆-alkyl, C₁₋₆-alkoxy, —OH, halo, and haloalkyl.
 10. The method of claim 1, wherein at least one of R¹ is —CH₃, —CH₂CH₃, phenyl, —CH₂-phenyl, or —CH₂-indolyl, wherein phenyl, —CH₂-phenyl, or —CH₂-indolyl may be optionally substituted by one or more groups selected from C₁₋₆-alkyl or halo.
 11. The method of claim 1, wherein at least one of R¹ is phenyl, and wherein phenyl is optionally substituted by one or more groups selected from C₁₋₆-alkyl, C₁₋₆-alkoxy, halo, and haloalkyl.
 12. The method of claim 1, wherein R_(y) is H.
 13. The method of claim 1, wherein the compound of Formula I is, selected from the following:

or pharmaceutically acceptable salts thereof. 14-32. (canceled)
 33. A method for inhibiting migration of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof.
 34. (canceled)
 35. (canceled)
 36. A method for decreasing viability and survival of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof.
 37. A method for inducing differentiation of a neuroblastoma cell comprising administering to the cell a therapeutically effective amount of a HDAC1, HDAC2, and/or HDAC6 selective inhibitor or a pharmaceutically acceptable salt thereof.
 38. (canceled)
 39. (canceled)
 40. The method of claim 33, wherein the inhibitor is selected from the group consisting of a compound of Formula I, Formula II, Formula III, Compound 001, Compound X, Compound Y, or any of the compounds in Table
 1. 41. (canceled)
 42. A method for treating neuroblastoma in a subject comprising administering to the subject a therapeutically effective amount of Compound 001, having the structure:

or a pharmaceutically acceptable salt thereof; Compound X, having the structure:

or a pharmaceutically acceptable salt thereof; or Compound Y, having the structure:

or a pharmaceutically acceptable salt thereof.
 43. The method of claim 36, wherein the inhibitor is selected from the group consisting of a compound of Formula I, Formula II, Formula III, Compound 001, Compound X, Compound Y, or any of the compounds in Table
 1. 44. The method of claim 37, wherein the inhibitor is selected from the group consisting of a compound of Formula I, Formula II, Formula III, Compound 001, Compound X, Compound Y, or any of the compounds in Table
 1. 